Method of determination of airscrew force field structure (versions)

FIELD: hydrodynamics.

SUBSTANCE: invention refers to experimental hydrodynamics, hydrodynamics and aerodynamics of airscrew and can be used in shipbuilding and aircraft building. Method includes force field created by airscrew rotation and carrier moving, use of visualising facilities and field structure registration by optical equipment. Thus airscrew rotary speed is established assuming production and stream maintenance of visualising facilities. Field is registered by scanning in two transversely-spaced planes, i.e. horizontal and vertical, in front of, and behind, the airscrew. Thus boundary layer, turbulence areas, increased and decreased pressure areas, airscrew expansion angles, and whole flow structure are showed.

EFFECT: high-accuracy picture of airscrew propeller environment flow.

5 cl, 16 dwg

 

The invention relates to a propeller hydrodynamics and aerodynamics of the propeller. The invention can be used in shipbuilding and aircraft construction.

The basis structure of the force field screw put the spatial structure of the dipole (the combination of source and drain with equal costs). We use the analogy with the electromagnetic field of the solenoid. Given the characteristics of the screw, tube current (power line) will be twisted in the direction of rotation (to simplify their spin on Fig.9 not shown). Propeller sucks mainly the upper water layers. The latter is due to existence before the drive screw vortex formation and its circulation in the vertical plane under the action of buoyancy forces and wind. This feature is reflected in the physical model of the screw (in its electromagnetic equivalent). The coil of the solenoid consists of two halves: the front half - mobile (its axis in a vertical plane describes the kind of sector-quadrant), the back half is stationary (electrical connection halves serial).

Another feature of the flow behind the propeller is the stability of the position in space of its axis and the least interaction with the environment, due to the rotation coming off the blade wiring harness (free vortices, see Fig 1 and 2, is derived the from (4)). While the wiring-vortices rotate around its axis and around the axis of the screw. This feature can be taken into account in the analog-solenoid as follows: the magnetic core is covered by a coil part. It unreached part of a considerable length, extended back (downstream) and has a screen on the side. Recent moves North pole of the magnetic field back or the source dipole downstream. The dipole model screw presents in inventions (10-16) with the exception of the last features.

Invention (10-16) can be analogues of this proposal. The invention (13) may be a prototype.

Thus, the force field screw asymmetrically. The longitudinal asymmetry in the vertical plane passing through the axis of the screw caused by the existence of whirlpool front of the drive screw and circulation (birth, development and disappearance). The specified leads to the fact that the density of lines of force above the screw may be significantly greater than the density of power lines under the screw. This asymmetry is also cyclical in time (see figures 9, 10). The suction of the propeller screw predominantly upper water layers contributes to the reduction of friction forces with decreasing depth (reduced static pressure). When a stable density stratification of the environment for the propeller are less dense layers in comparison with the environment. They splawa the t and can oscillate with a frequency of Vaisala - Brenta about some of the horizon.

In the prototype (13) are not considered adequately stabilizing properties of the spin flow with the drive screw, and the impact of turbulence in a cocurrent flow (ST) on the character (picture) distribution of the field in space.

The aim of the invention is to create a more complete picture of the force field of the propeller as the propeller and the air. Given this picture, it is possible to optimize the characteristics of the propeller and propulsion. The main provisions of the model is universal and applicable to missile and other drivers.

The invention will discover by considering figure 3 (photo from (4)). It represented a force field from a screw propeller of the ship rendered by the gas bubbles. The ship moves at a speed of 45 km/H. Field consists of divergent ship waves (KV) and narrow ARTICLE. The structure of the ARTICLE says about the lack of complete mixing and blending, which allows you to apply a zone approach to the analysis and to highlight the cross-section V. the area of the hull (LC) and the area of propulsion (EP). Gears is a peripheral part of the ARTICLE, and it is due to part of the boundary layer on the hull. This part of the inferior nasal diverging waves and were not included in the structure SECTION. Visualization KV and ARTICLE produced gas bubbles. It is possible to visualize and other means, for example by injection under Rosenau water (air).

Structure determination of force field screw is a transverse scanning characteristic of his plots. Highlight these areas, remembering that power line fields are closed, go through the drive screw, a lot of them and distribute them in space limited force field background. The initial amount of vitality capacious vortices in the field is determined by the number of blades (one blade is one of the vortex). Each vortex closed in space. He is born on the propeller blades (attached vortex). The rest of it is free. Vortex theory N.E. Zhukovsky has a significant drawback, considering only the attached vortex. The calculation of the blade for strength taking into account only this vortex is also incomplete and the calculation of the minimum. The remainder of the vortex is unaccounted for. The technical result of the present invention lies in the fact that on its basis it is possible to build a sophisticated calculation of the strength of the blades. The choice of the values of factor of safety is justified.

Let's divide the ARTICLE into sections, elongated along its axis (see figure 3 and Fig). Site 1 is located in front of the screw (suction side). Its beginning is in the fore part of the ship, and the end in the drive screw. The transverse dimensions substantially exceed the width of the ship. Its outer contours (in the horizon of the flax-section) can be represented in the form of part of an ellipse, which has a longitudinal axis substantially exceeds the cross. Longitudinal axis aligned with the axis of the ARTICLE. Rotating the blade (suction surface) create a rotating low pressure area. These areas are directed force line (tube current). In accordance with this, in the suction flow has both axial and circumferential components of velocity. The last cause the occurrence of vortex formation. Thus, the larger the diameter of the screw, the more torque (M˜D5where M is the moment, D is the diameter). The increase in diameter in 2 times is the increase in the moment of 32 times. The amount of emphasis grows slower (˜D4where - emphasis). The increase in diameter in 2 times is increased emphasis in 16 times.

Thus, with increase in the diameter of the screw circumferential speed increase is significantly greater than the axial. The result also increases the intensity of the vortex formation in front of the screw. There are factors that can strengthen or weaken the vortex formation. To promote long-term factors include double-shaft model media with internal rotation of the screws (11). She has a torque from the housing is directed in accordance with the time vortex on its ascent. When external rotation of the screws (Fig) moments are directed oppositely, what hinders the development of the vortex. Ave is a single-shaft models may dismemberment whirl on a few of vortex formations. There are short-term factors that could either increase or reduce the maelstrom. In the General case, the determining factor is the ratio between the kinetic energy of rotation and translational motion in the stream before the drive screw. Their equality defines predictive the state of a thread.

The existence of the vortex is cyclical in nature. As a result, and the cyclic changes of emphasis and bending moment acting on the shaft of the screw. In addition to the buoyancy force (the direction depends on the type of density stratification of the environment: the case of sustainable - up, when unstable - down) and power from the counter-flow vortex acting nasal diverging waves (NRV). This complicates the trajectory of the axis of the vortex and its interaction with the boundary layer on the body of the carrier. As a result, the flow of water is a lot of gas bubbles due to the following reasons: the capture surface cavitation on the housing and blades, as well as reducing pressure before you drive screw. Given the above, the first scan will do before you screw. Thus discoverable beginning NRW, gear and ZV. In the structure between the LC and ZV is viewed period with a minimum of bubbles, indicating a weak interaction between these zones. Turning to the model field, should the drain be placed on the suction side of the VI is the and the South pole is near the end of the winding of the solenoid.

Plot 2 is located immediately behind the screw (see figure 3 and 13). Its special feature is the sharp reduction of the divergence angle of the ARTICLE from about 50 deg. to 1 and the presence of two narrow strips. Here we use a 2-shaft model media, determining existence of two ZV. Thus the interaction between them is minimal. This is evidenced by the cross-plot of average temperature, measured at depths of 3, 2,4, 2 and 1.2 m at the age of ARTICLE 8, and 15 min (distance down the ARTICLE accordingly 6000 and 11250 m, see(4)). In (4) also notes that the sustainability of such thermal effects are sometimes very long (hour or more). These plots are presented in figure 4 (age 8 min) and figure 5 (age - 15 min).

Cross-plot of average and pulsation speeds, measured in model experiments (13), show the following (the ratio of X to D is in the range from 1 to 10, where X is the distance down the stream, D is the diameter of the screw). Plot of average velocity is maximum on the axis of the ARTICLE, falling to zero at the periphery (the velocity is directed away from the screw). Next, the speed change direction on the opposite (to screw), grow, having a maximum, and decreases to zero at the periphery. Therefore, the main stream, the current of the screw surrounded by a peripheral, the current to the screw on the suction side. While its transverse size increases as the app is to achieve. In other words have two opposing flux: Central and peripheral (reverse flow). Figure 3 visible border between threads at a distance of 230 meters Plot of pulse velocity has a maximum in the interval between threads, where you change the direction of the velocity or direction of the power lines.

The nearest space for the propeller becomes filled with gas bubbles, well-visualizing the boundaries and structure of the ARTICLE. Their ascent is difficult due to the presence of powerful high-speed field. In this part of the bubbles dissolves under the action of excess pressure. With decreasing pressure downstream of the gas released by visualizing the structure. In reducing the intensity of turbulence ascent of the bubbles is facilitated.

Plot 2 has the greatest spatial stability. This is due to the fact that ZD is the set vitality capacious vortices-harness having a spin around the axis of the screw, and around its own axis. Specified causes, and the least interaction with the environment. However, such interaction exists throughout sections 2 and 3 (see figure 3 and 13) and it is unevenly distributed along their length. In the place where the axial speed forward and reverse currents are equal, the interaction between them is minimal (Fig, section 10). At the point of maximum difference against the opposite speeds FRI and has the largest interaction (see 3, the crossing angle of the extension of ARTICLE 50 deg. up to 1 deg., Fig, section 9). ZV is a direct current (DC).

On Fig shows a diagram of forward and reverse currents (PT and OT) in the horizontal plane (upper part) and an approximate schedule changes downstream FR (13) and (14), and the pressure difference from background values (15). According to 13 and 14 are axial velocities. The dependence of the 15 - increment of the pressure on the axis of the ARTICLE. At site 2 have negative increment pressure, increasing as it approaches the screw, due to the increase in centrifugal forces. At site 2 have a positive increment of pressure, due to the predominance of axial forces and velocities. In section 10 of the axial velocity FRI and FROM equal. There is a system of pairs of forces and moments without beats and minimal interaction with PT FROM, as well as the minimum centrifugal force, circumferential, and radial velocity. Section 9 is the maximum axial velocity FRI and FROM (extreme). The latter explains the reason for the change of the angle of divergence of the ARTICLE with 50 deg. up to 1 deg. (figure 3). Section 11 is the maximum pressure and the minimum axial velocity FRI.

A relatively thin strip of reverse flow, visualized bubbles (it narrows down the stream ST), characterizes the intensity of the pulsation velocity occurring at the boundary between the PT and the (backward induction is m). When driving the screw increases the gradient between the speeds FRI and FROM (they have opposite direction), increase the velocity fluctuations, increased turbulent diffusion of bubbles and increases visualized band FROM.

Consider the picture of diverging waves, PB (3 and 13). Its feature is the presence of NRW from the case of the carrier jet and PB from areas of high pressure, 2 ST. This NRW and PB are the nonlinearity due to the following reasons. The initial part NRW appressed to the axis of the ARTICLE deficits pressure between sections 7-10. The final part NRW and RUST are influenced by peripheral part of the force-field of the jet. The velocity of wave propagation with increasing distance from the axis of the ARTICLE begins to turn in the direction of movement of the ship. At the ends RWST (3) if the age field 35 C and at a distance of 440 m width of the field is estimated at 520 m (ship length 130 m, the speed of 15 km per hour, the scale of 1 mm = 5 m). On Fig NRW indicated by the numeral 16 and RUST - figure 17. At the age of 35 with the main part of the kinetic energy converted into heat. The turbulence intensity is significantly reduced. Vortices weaken and grow their scale. Speed crushing vortices decreases. Increases the exit velocity of bubbles on the surface. Their number in the structure of the ARTICLE is reduced. Growing intermittency plots the bubbles and without bubbles. As reducing excess pressure and ascent ZV born new bubbles of dissolved gas.

ZV and separated FROM the strip with a deficit of bubbles. This is due to the structure specified band, which is a system of small eddies. In each of the whirlpools have at least a pair of forces, due to the opposing currents. The trajectory of the bubbles takes place from ZV to the axis of the vortex, care about depth and forth FROM. The magnitude of the forces involved in the pairs decreases as you move down the flow of the ARTICLE. This lowers torque and reduces the amount of bubbles coming in FROM.

Section 2' is characterized by a significant reduction of the axial velocity. The boundary between ZV and not visible. The intensity of eddies and small bubbles are beyond their control. They come to the surface. Their number in the structure SECTION can be significantly reduced. However, there is excess pressure in ZV. The structure of the ARTICLE is a complex interplay of a large (vitality capacious) vortices created a 2-shaft propulsion, propellers which rotate counter. Intermittency increases. Small vortices have low energy. They are not able to keep the bubbles and not visible. However, turbulent process develops.

P. Bradshaw (7) gives the following definition of turbulence. Turbulence is three-dimensional unsteady movement, which is caused by the stretching of vortices creates a continuous distribution of the velocity uctuation in the wavelength interval from the minimum defined by viscous forces, to the maximum defined boundary conditions.

Large vortices have the best ability to interact with secondary currents create voltage Reynolds. In turbulent vortices take away energy from the mean flow and deformed fractions and pass it on to the small dissipative eddies.

Possible development of turbulence down the ARTICLE to consider how the existence of vortices of different generations. Each generation passes these stages: birth, deformation, fragmentation, and extinction. Transfer of energy occurs from the middle reaches to large vortex progressing from vortices mid-size to smaller. The highest energy density have large vortices (longer trapped air bubbles). Down the ST scale vortices increases, causing the displacement of the spatial spectrum towards lower numbers. Similarly shifted and the maximum energy of the spectrum. Decreases its absolute value, leading to an increase in the sensitivity of the measuring equipment. The spatial resolution of the instrument should decrease. Due to shrinking transtorno spectrum reduces the required width of the frequency spectrum (bandwidth) of the measuring equipment.

Estimated life time of initial velocity field of the propeller in the ART can be made according to the formula

where W is the kinetic energy transferred by the screw in the ART; m is the mass of water in verse; ε - the rate of energy dissipation.

In accordance with the first hypothesis of similarity A.N. Kolmogorov statistical characteristics of small-scale components of fully developed turbulence are determined by two dimensional parameters ν and ε. Of these options, you can write the following equations for the smallest turbulent eddies

and

where: η - size τ -, ε dissipation rate of kinetic energy, V is the velocity of the vortex, ν - the coefficient of viscosity of the medium.

Conditional end of the segment 2 is located at a distance of 260 m at the age of 21 C. At the end of the plot begin to be viewed large vortices with opposite direction. Transversal stern waves, human papillomavirus (HPV) are not visible. Evident complicated picture overlay NRW and PBA. In accordance with the weakening of the force field decreases the bending waves in the direction of the ship. Width FRI, measured at the beginning of section 2 and at the end of the section 2' increased from 10 m to 36 m At site 3 width changed from 36 m to 68 m Of e which CSOs can conclude that the main fraction of the kinetic energy, converted to heat, falls on a plot of 2, i.e. for the period of time in 21 C. When this SD and SD are in a twisted state (sustainable patterns). SD and SD have superstability based on double twist. Spin around the axis of the screw has a higher kinetic energy compared to the spin axis of the blade.

Turbulent processes in free wiring-vortices are the processes of promotion. Rotated about the axis of the blade ends earlier (less energy). Rotated about the axis of the screw is much longer (several orders of magnitude). For this reason, in the structure of the ARTICLE mainly viewed large vortices. The process of unwinding should be considered as the braking process, blurring the boundaries of the vortex, reducing the peripheral speed etc. the Action of centrifugal forces when you double twist specific. Outside they are directed to the periphery of the ARTICLE inside to the axis of the ARTICLE (considered vertical, transverse section). The specified leads to increased centrifugal forces and to decrease, leading to an asymmetric distribution of bubbles in the structure of the loom-vortex (figure 3).

Plot of average temperature, measured transversely to the ARTICLE (4) talk about the sustainability SECTION and a small interaction between SD and SD at a distance of 12500 m, U is of the depth location of the lower boundary of the ARTICLE (4) show she rises over time. Angle tilt boundaries in relation to the horizon is 5-13 min or 1.32 to 4.65 m climb to 1000 m path. On the trajectory ZD is the area of greatest ascent rate, which leads to the increase of gas bubbles in the structure of the ARTICLE.

On Fig presents a simplified geometric model of the force field screw (longitudinal section). The symmetry of the model relative to the longitudinal axis (horizontal section) occurs regardless of the depth of the screw arrangement and density stratification of the environment. The symmetry in the vertical plane depends on these factors. With increasing depth of immersion of the propeller in the field increases the asymmetry due to the formation and circulation of the vortex in front of the screw. In the transition from indifferent stratification to a stable horizontal dimensions of the field are beginning to significantly exceed the vertical.

In the field can be roughly divided into the following volumes. 1 and 4 transitional volumes - region (hemisphere, more problemcode rotation), which have a significant radial velocity greater than the axial. In section 1 develops a whirlpool and there is a shortage of pressure. In region 1 there is excess pressure.

Areas 2 and 2' contain a direct current, FRI, current from the screw. Their volume can be replaced truncated cone, the smaller base of which is placed on the screw. Given the concentration of kinetic energy at the periphery of the screw, PT is located on the periphery of the cone, inside the cone are volume environment with lower energy density. Excess pressure maximum at the periphery of the cone. In accordance with the rotation of the blades rotates and the region of high pressure. Each blade creates a region of low and high pressure, similar to the rotating blades. They are components of the total pressure field (power).

Area 5 and 6 contain the reverse flow, FROM the current to the screw. Their volume can be represented in the form of a hollow cylinder (cone), surrounding a Central cone PT. These areas have the background pressure, which is a simplification. At least there is a pressure gradient directed toward the screw. The gradient determines the existence FROM. The latter is concentrated in the cavity of the cylinder.

FRI and form a closed circuit system, rotating under the action of the screw. To analyze the resultant of the velocity field into three parts: the axial, radial and circumferential (tangential). For simplicity, we reduce to the minimum the interaction between PT and throughout their oncoming traffic. Then we can conclude that in regions 1 and 3, the axial velocities are transformed into radial, mixed. In section 1, the velocity is directed towards the axis of the screw in the area and 3 from the axis. When this is all over circumferential speed does not change direction.

On Fig presents a graph of the axial velocity FRI and FROM. PT is for braking. FROM is over-clocking. PT has a short section of the acceleration and long - braking, has a long stretch of acceleration and short - braking. There is a place where the velocity of PT and equal (section 10). The circuit is based on Fig is the model field of the screw as spatial twisted (rotating) dipole with equal costs. This equality is observed at jet. In other places of the path PT and equality is not observed due to loss of energy flows from friction (transfer of kinetic energy into thermal energy). The farther away from the screw, the greater the loss and the lower the consumption, the power flow (mass, passing through the cross section of the circuit per unit of time). The latter is expressed as a reduction in the flux density, i.e. in the reduction of weight, prohodjashei per cross sectional area per unit time.

Between FRI and FROM there the boundary area, where acceleration and turbulence intensity is the greatest. Here the turbulent mass obeys turbulent laws, which reduces the interaction between FRI and FROM (2). Rosmarin O.N. notes that turbulent swirling jet in a cocurrent flow has a greater resistance than the laminar swirling jet in a cocurrent flow. Between Sech is of 8 and 10 (Fig) speed FRI exceed speed, which leads to the existence of "pairs" of forces, creating a system torques beating directed to the periphery of the ARTICLE. Between the sections 10 and 11 (Fig) speed FROM exceeding the speed of PT, which leads to torques beating to the axis of the ARTICLE.

Pig is a high-quality picture of the force field of a screw (not drawn to scale). When clarification is necessary to reduce the longitudinal dimensions compared with the cross. On the basis of the law of conservation of momentum, you can get an approximation of the ratio between the average speeds FRI and FROM

or

where: VFriVfrom- average speed, DFri, Dfrom- the average diameters of the cross sections of the volume. The volume of PT are presented in the form of a cylinder, and the volume - in the form of a hollow cylinder. More quickly reducing the speed of PT compared to the speed increase FROM due to the generation of excess pressure in the regions 2' and 3.

Torques, beating out (on the periphery of the ARTICLE) to help set the internal border FROM the (lack of bubbles marks the boundary, see figure 3). Bubbles made of PT (see the gap between the sections 8 and 10), render only the inner part and FROM his angle of entry into the hemisphere 1, angle = 50 degrees. The way to join the invisible part of the drive screw over the false, with the change of sign of the axial velocity. When the mass movement of water FROM the jet grow circumferential and radial components of velocity. Twisted part FROM has the greatest dimensional stability up to a critical condition, after which there is a growing instability caused by the formation of a vortex in front of the screw. Hemisphere 1 is drawn forward, is reduced in diameter, turning into problemshed rotation, its stability in the space decreases. Occurs, the circulation of its axis in a vertical plane, and the resulting pressure pulsations and speed in the space surrounding the screw. When the carrier frequency of the pulsations is determined by the speed of rotation of the screw and the number of blades, and the frequency modulation of the velocity of the vortex and the vertical plane. In accordance with this change (pulse) and the geometrical sizes of PT and OT. Note that the presence of acceleration and deceleration on FRI and due to the impulse action of the screw on the fixed mass of the environment.

Consider the process of transferring the kinetic energy of the PT and FROM moving downstream of the screw. The energy from the screw covers back and sides through FRI, creating an expanding structure. Energy is transferred from areas with excess pressure in the area lack. For the propeller has Corot the cue section, where the swirling flow, the axial velocity maximum. Between sections 8 and 10 (Fig) axial velocity FRI higher axial velocities FROM. The kinetic energy of the PT is passed through FROM the boundary layer by beating small whirlpools. In section 10, where the axial velocity FRI and equal, there is no energy transfer. Obviously, the decrease in energy transfer when moving from section 8 to section 10 is gradually approaching zero. When this maximum is in section 9.

Between the sections 10 and 11 of the energy in a similar way goes FROM on FRI, since the axial velocity PT is less than the axial speed. When this maximum is in section 11.

Define the width FROM should be based on equality of momentum on FRI and FROM. In this case there is error due to the presence of turbulence. The latest is difficult. Define the width FROM section 10. The equation of motion amount is

where: mFri- weight of PT, VFri- speed PT, mfrom- weight of Vfrom- speed FROM. As the equality of the velocity, density and increment of the longitudinal coordinate, the equality of momentum can be replaced by equality areas: SFri≅Sfromor D2from≅2D2Fri. Where: EFri- diameter PT, Dfromthe diameter. The result is: D =1,41 DFri. For figure 3, the width is FROM 10 m (width PT equal to 50 m).

Note that the maxima FRI and must have the same longitudinal coordinate, i.e. lie on the same section 9. Only in this case is the explanation of the nature of the bubble changes FROM (the presence of pronounced extremum, the transition angle extension ARTICLE 50 deg. up to 1 deg.). Given the formula 3 and neglecting the heat losses in the ARTICLE, it can be concluded that the areas of triangles PT and should be different (graph Fig). When you account for the loss of the area of a triangle PT must be less than the triangle FROM. End FROM (Fig, section 12) can be identified by having a straight through found two points in sections 9 and 10 to the intersection with the horizontal axis (the speed of change and used). Speed values are averages over the cross section. It is obvious that the calculation has a large error. However, using the law of conservation of momentum, you can set the paths PT and FROM.

Refer to Fig.6-8 (4). Figure 7 and 8 presents a force field from a passing vehicle with a low weight chassis and deeply immersed screws (2-shaft model). A characteristic feature of the field is the lack of bubbles on its axis over the interval equal to about 1.4 length of the hull. While the bubbles are concentrated at the periphery. Given the above, it is possible for prisoners who report the following. The photo is viewed FROM rendered by the bubbles. His angle of entry into the space in front of the drive screw 50 deg. The presence of a large number of bubbles at the initial part due to the presence of large surface interaction between FRI and FROM. Next, the Central region is depleted of bubbles due to their emergence and disappearance. Their depth location less than at the periphery. Peripheral bubbles to float longer.

Ascent PT also has a place, and it determines the angle of divergence of FROM equal to 1-3 degrees. The boundary between PT and FROM the home site is not visible because it is located at a depth, and the upper space is filled with bubbles. PT is inside of. PT has fewer bubbles, since the center of area 1 is located at a greater depth (cf Fig with figure 3). Bend the ends RNV, due to the direction of the field lines, also occurs.

Figure 6 presents the trail from the boat. Due to the very high speed and shallow location of the screws FRI and have a flat character in space (horizontal dimensions greatly exceed the vertical). This structure takes a more extreme position in the range of surface fields. Average position belongs to 3. The boat is in the regime close to glissiruyuschie. The cutter has a sharp deadrise nose, Bo is lsoi the collapse of the nasal frames, decreasing deadrise, gradually turning into flat bottom, sharp cheekbones and aft (5). It defines the geometry of the COP. Due to the large centrifugal forces FRI depleted bubbles. FROM receiving a large number of bubbles of gear. High speed boat causes a high and rapid RH and the seizure of gear FROM a large number of bubbles.

Let us return to figure 3. On it has light and dark bands radiating out from the ARTICLE. Dark areas are areas in which the energy density above background (areas of high hydrodynamic pressure). Their structure does not respond to background exposure, for example in a moderate wind. They have a smooth surface. Their distribution on the square, you can draw the outer lines of force field, the direction of its lines of force and character. A field is a single pulse of energy having a sloping fronts and moving behind the ship. The visible size of the field are of the order: longitudinal - 650 m, cross - 260 m Field has the shape of a truncated cone whose axis is aligned with the axis of the ARTICLE, the small base close to the screw, and large removed (see Fig areas 2 and 3).

Because the field of high pressure moves, it creates a system of diverging waves, PB, having a relatively wide range (see range single pulse). Between the stern of the ship and the small bases of the of the cone there is an area of low pressure. Its shape can be represented in the form of a small cone with the base at the rear and top with screw on its axis.

Considered fields are physical proof of the dipole model and its electromagnetic counterpart. These fields define the characteristics FROM its direction, intensity, shape (the angle of entry into area 1, Fig). If PT is created by the screw, FROM the regions of high and low pressures arising from the operation of the screw. The view from the top is well picture of the distribution of the RV. The crest of each wave is located between areas of high pressure (divergent dark spots). The presence of waves and the structure of the talk about the structure of the field of high pressure (region 2', 3 - dark, solid and tapered spot). The peculiarity of the field is the presence of pulses (beats). As you move down the flow of the RV amplitude decreases as the frequency increases, which is a common reaction volume of water on a single pulse of energy.

Mid-power field diameter can be set by the greatest curvature of the ends of PB (where power lines are the largest angle with the PB). It lies in the range 340-420 m, measured from the screw. When measured from the nose of the ship mid is within 470-550 M. Thus, the end of the field may be at a distance 680-840 m (940-1100 m). Prolonged ARTICLE about the region with higher pressure causes a slow liberation of gas bubbles, that allows to visualize the ARTICLE. Such conditions can in FROM the gas component.

PB is a structure in which alternate sections of high and low hydrodynamic pressure. Each area of high pressure creates a system of forces directed perpendicular to the front of the wave propagation and along its course. The system forces the first section operates in an unlimited space (more precisely in the half-space). The system forces the second area of high pressure acts in the space bounded by the first area of high pressure. The latter causes a rise of the water level in the interval between these areas. While there is some expansion of the gap between the sections as the distance from the axis of the ARTICLE (linear extension). The yacht proceeding under sail, this extension should be linear.

In order to specify parameters path (path or channel) FRI - FROM apply Ohm's law to complete the circuit. However, let's agree that the channel is impermeable wall, the hydrodynamic (HD) settings have focused nature. Power flow (mass of water passing through the cross-section of the channel per unit of time) has a dependency

where: E - photocopieuse force (difference DG pressure), Zin- full interior with rotisserie the power source E, Zto- the impedance of the channel (see Fig, 15 and 16).

Resistance Zinis

where: R is the resistance, LInis the inductance, CIn- capacity, ω is the angular frequency of the ripple of the stream (ω=2πf), f is the temporal frequency. : E - 1, R - 2, C - 3 and L - 4 (see Fig).

Active DG resistance of the screw caused by the surface roughness of the screw and the viscosity of the medium. It is the energy of the jet is converted into heat. DG inductance and DG capacity are reactive resistance of the screw. RG inductive resistance of screw - the ability of the screw thread, reducing its axial speed, and the ability of the stream to spin, while maintaining its axial velocity. DG capacitance of the screw - the ability of the screw to give the energy flow, creating areas of high and low pressure, i.e. to accumulate energy.

Resistance Ztois

where: Rto- the active resistance of the channel, Ltothe inductance of a channel Withto- capacity of the channel. Thus: R - 5, C - 5 and L - 7 (see (Fig).

Active channel resistance caused by the friction FRI and FROM the walls of the channel and the friction between their layers. The resistance increases with increasing channel length, reducing its cross section and with an increase in the density of the medium (what Arsenium temperature and increasing salinity). It increases with increasing depth of the channel due to the increased pressure. Similarly depends on the resistance of the screw.

RG inductive resistance of the channel depends on its form. Than silistea channel, the greater its resistance. The shape of the channel depends on the hydrological environment. The presence of inversion layers complicates the form. It is not always field propagates in a straight line. It goes along the line of least resistance. Large screws have greater resistance.

DG capacitance of the channel depends on its volume. The greater the volume, the more capacity you have, the less capacitance. The capacity depends on the location of the bottom surface, the jump density. The large screws high capacity (less capacitance).

The behavior of flow in the system the screw channel and the bearer of the screw depends on their mutual influence and primarily on the characteristics of the screw. The last is the only active element, which plays a major role in shaping force field. Other elements play a supporting role. They are passive and unable to fundamental changes. The screw is amplitude-modulated kolebanii. FROM the role of feedback that can be both negative and positive, i.e. to weaken or strengthen doubt the Oia.

A special case is resonance, which significantly increases the amplitude of the forced oscillations in the system (frequency of external action coincides with the natural frequency of the system). The latter lie in the ultralow-frequency range. In the same range is the frequency modulation 9 of the carrier frequency oscillations 10 from rotation of the blades, i.e. the frequency of circulation of the vortex. On Fig shows the electrical analog of the considered DG system (Fig) and consistently simplified (Fig and 15). In similar under the modulation frequency of 8 means the impact on the fixed volume of the medium (its mass) passing propulsion and under 10 frequency (simplified dash, really - like presinusoidal) - impact blades. In case of equality of these frequencies is the greatest compensation inductive capacitive impedance and a decrease in the total resistance to a minimum. A consequence of the resonance is significant changes in the magnitude and vector direction of the stop screw, the appearance on the shaft bending moment, and pitching (on the circulation side and pitching).

The influence of the media corps screws on the characteristics of the considered system are as follows. In the case of the ship change characteristics region 1 (Fig). In the case of aircraft parameters change regions 2 and 3. The case is of arable with low weight will replace the flat plate and place it in front of the screw, on its axis. Obviously, the plate is partially separated FROM the two symmetric flow, reducing spin and DG inductive resistance of the system. It is possible the breaking of the common whirlpool for two. Increases the DG active resistance system.

The hull of the ship with great completeness (to simplify the analysis) can be replaced by two mutually perpendicular plates: long longitudinal and short transverse. The latter significantly increases the DG active and capacitive resistance of the system decreases DG capacity).

In the hydrodynamic circuit, the role of the capacitor with a certain capacity is the period of the loop, where there is a difference hydrodynamic pressure, i.e. the period between the volume before screw (deficit pressure and volume for the screw, where there is an excess pressure. As the screw here accumulates potential energy turns into kinetic in the form FROM. Role coil (solenoid) with a specific inductance plays a swirling flow PT. The larger the diameter of the screw, the greater the swirling flow, the higher hydrodynamic inductance. It creates a delay in the onset of maximum (minimum) at FRI. Reactive DG resistance path PT and create an oscillatory process: changes in comparison with PT happen to delay, with a shift in phase.

In the analysis of PB in smosna validation of the Doppler effect. The last is to change the frequency of the received oscillations in comparison with the frequency of the emitted depending on the nature of the motion of the radiated wave and the meter. When oneness movement fixed period increases, and when the counter is decremented.

Structure determination of force field screw is preceded by the following actions.

1. Select the medium of the screw and is determined by its tactical-technical specifications: displacement, dimensions, capacity of the main power plant (EPP), the design of the thruster, the shape of the contours, etc.

2. Select the media retainer (measuring) equipment. While the media with their presence should not distort the field. As the carrier can be: helicopter, airplane, and others. You can use fields from the bridge or special events.

3. Selected area setting fields with known hydrology, in which there are no strong currents and old force field. The area should be removed from the shipping lines, banks, and have sufficient depth.

4. Selected windless and Sunny weather (noon).

5. Selects the horizon and the point of observation, providing optimal position fixing equipment relative to a line passing through the medium of the screw. The position must be symmetric and to provide the necessary solution for the monitoring field. The plane of fixation of the field depends on the location of the carrier of the screw relative to the boundary line. If the carrier of the propeller in the subsurface layer of the plane of fixation of the horizontal field. For the air screw located far from the ground plane can be both horizontal and vertical.

6. Select the renderer force field. In natural conditions for media mushroom screw, running on medium speed in the subsurface layer, such means are air bubbles. In the laboratory can be used dyes. In the case of a propeller, it is expedient in the force field to implement in a small amount of compressed and tinted air. Tinted water under pressure can be injected in the pitch of the propeller.

The invention consists in that, crossing the force field of the screw and measured, identify the characteristics common to the field and its parts. The signs define the boundaries of the field and its components, their shape and intensity. The signs revealed by comparative analysis of the measured values with the background values. This analysis is based on the dipole model force fields of the screw.

The first way consists of the following :

1. In the unperturbed environment, without abnormal characteristics is created Sylow the e box screws (screws) when moving the carrier along a straight line with constant velocity at a certain horizon.

2. The position provides the necessary coverage and resolution fields, is his photo, film and video.

3. Are the positives with different magnification, providing the necessary coverage and resolution when viewing and analysis fields. Similarly prepared film and video.

4. The first visual scanning (crossing) is carried out before the screw and fixed the boundary layer on the body of the carrier is measured by its width, qualitatively determined by the degree of turbulence, fixed form of the boundary layer and its change as it approaches the screw. However, the rapid increase in the width and turbulence as it approaches the screw indicates the overwhelming influence of the field on the boundary layer. In the case of low turbulence (low speed movement of the carrier) in the boundary layer can be viewed whirlpools (one on each side of the carrier). Whirlpools synchronously generated in the bow, move to the screw, increasing in diameter, and disappear in the stern at the same time. Then again arise in the bow. When full body media whirlpools can temporarily disappear in its middle part and then to appear near the stern. Their presence suggests that the value of the peripheral speed greater than the axial.

5. The second intersection is C the screw, where the ARTICLE starts to extend fragile under 50 deg. Fixed PB, alternating zones of high and low pressure (their width and the initial direction of the ridge line). Recorded the presence of the gap between PT and depleted air bubbles. Measured width FRI and FROM (that part of it, which is visualized by the bubbles). When this width is equal to the sum of widths, measured from both sides of the ARTICLE.

6. The third intersection is where the angle of expansion varies FROM 50 deg. up to 1 deg. Recorded and measured the same parameters (see section 5) and measured the distance along the axis of the ARTICLE from the point of its intersection fragile under 90 degrees. to screw the stern of the carrier). Calculate the ratio X/D, where: X is the distance, D is the diameter of the screw. For the case of figure 3 the ratio is 20 (L=2 m).

7. Found on the image to the ARTICLE output gap between PT and FROM the edge of the ARTICLE by holding the line along the axis of the gap to the intersection with the edge of the ARTICLE. In the found point is the equality of the axial velocity FRI and FROM. To this point the ratio X/D=130.

8. Fourth crossing through the point found in item 9 perpendicular to the axis of the ARTICLE. Fixed PB and measured their curvature, i.e. the angle between wave crest line of the starting location. Define the character of the curvature and the width of the force field at the end of the RV.

9. The fifth intersection of proizvodid is by the approximate center of the area of excess DG pressure. This line should divide the figure with a dark color (they are located on both sides of the ARTICLE) so that their parts have equal area. Measured the width of the force field and the distance from the screw. For figure 3, they are 400 m and 440 m, respectively (the ratio X/D=220).

10. The sixth intersection is at the end of the force field. In this place formed a cone-shaped area, where DG pressure decreased to the background (the axis of the cone is aligned with the axis of the ARTICLE). At the periphery of the field remains an area of high pressure in the form of a hollow cone. A significant part of the ARTICLE is the background pressure, which promotes the release of gas bubbles and diffusion currents. Measure the distance from the screw and calculated the ratio of X/D=310.

Possible additional crossing, for example: in the alignment screw (seen the disappearance of eddies and measured the width of the PT and OT), in the interval between the third and fourth intersections (recorded and measured similar claim 5 settings), and in other places in the ARTICLE.

In natural conditions for propeller method is applicable for fixation of field in the horizontal plane. In model conditions it is possible to commit the fields and in the vertical plane. For propeller method is applicable in both the horizontal and vertical planes.

How is the graphic. However, when using the form of the apparatus it is possible to register fields in dynamics, i.e. fixation of velocities and accelerations. In the analysis of the field all areas defined by coordinates with origin at the center of the screw.

The second method is similar to the first. The difference is that the fixing force field is carried out in two mutually perpendicular planes, for example in horizontal and in vertical.

The third method differs from the first by the fact that the measurements of the main characteristics of the field. In the case of probe measurements are carried out at a certain (constant) depth, for example at a depth axis of the screw. In the case of non-contact sensors measurements are performed on the surface of the water environment. While the carrier of the measuring equipment should move with constant speed far exceeding the rate of change of the characteristics of the field. Its trajectory can be similar to the first method, i.e. the movement of the long transverse lines crossing the field in its characteristic places: in front of the screw (e.g., at a distance of half the length of the hull), the target drive screws directly behind the screw, with the screw in place with the largest exceeding the axial velocity on FRI speeds FROM, in place of the equality of these speeds, the largest exceeding the average speeds of over speeds FRI, approximation of axial velocity FRI and FROM zero. Preferably, h is the ordinary tacks were parallel to each other and perpendicular to the axis of the screw. The tacks can be carried out simultaneously or sequentially in time. Beginning and end of each measurement gals must go through the background.

When using the contact of the first three sensors measuring the tack of appropriate conduct with brackets fixed to the vehicle. The sensors are in the water and connected by a cable to the onboard equipment. The rest of the tacks similar to the one described. While the carrier of the measuring instrument may be self-propelled or towed buoy. Towing can be made both from the ship and helicopter. In some cases (the study of fragments field) sensing can be done from the bridge, producing a reciprocating measuring tacks. A mandatory requirement is the least impact of the field of media gauges on the pitch of the screw. The latter is achieved by the small weight of the body, making sensors forward and towing.

When using non-contact measurement requirements are simplified and reduced to the imposition of the sensors of the boundary layer of the medium and to the error from his force field.

Sensing (intersection) can be made either in horizontal or in vertical planes. The latter should be carried out in the diametrical plane of the screw. Can be a vertical plane, ravneet is present from diametrically.

Before sensing compiled his map with the origin of the coordinate system in the centre of the investigated propeller. In the process of sensing continuously recorded field parameters, the current time and off-nominal events. All information linked to the plan. Adjustment of the measuring apparatus Pets once at the beginning of work in the measurement of the background.

Can be measured by the following parameters: speed, pressure, temperature, salinity, density and gas content (oxygen and carbon dioxide). The main parameters are the velocity, pressure and temperature. Measured as the average values of the parameters, and pulsation. Measured speed: axial, circumferential and radial direction. On the axial velocities are recorded FRI and they ripple the presence of a boundary between PT and ot and the presence of turbulent areas. Largest circular velocity is fixed spin FRI and FROM and the presence of eddies. The magnitude and direction of radial velocities recorded transition region (1, 2', 3, 4 Fig). In section 1, the velocity is directed towards the axis of the screw. In regions 2', 3 and 4 velocity directed away from the axis of the screw.

The magnitude and sign of the increment of the pressure tests the depth of the sensors, the presence of areas and areas of high and low pressure, the geometry of the RV and confirmed by the Doppler effect, which consists in the change of frequency is fixed PB in comparison with the frequency of the radiated ARTICLE RV depending on the magnitude and direction of the carrier speed of the probes. The curvature RV is checked if there are three points that belong to the same wave. If necessary, are intermediate tacks.

At an average temperature value and compared to the background is determined by the fence screw the upper layers of the medium. This purpose can be used, the readings of the meters salinity and density. The readings of the measuring gas content in the water is determined by its dynamics in the ARTICLE.

Considered parameters are measured continuously and recorded in analog form. The latter is useful for quick analysis. Possible selective recording and digital recording and processing of information.

As contact sensors can be used: thermo-anemometer, vane, thermometer resistance, membrane sensor, electrochemical sensor, conductivity sensor, etc. as non-contact sensors can be used infra-red, laser, acoustic, and others.

The third method consists of the following :

1. The first sensing takes place before the screw. Measured: width of the boundary layer (middle and pulse rate), turbulence (pulse rate), width (middle speed), spin (circumferential speed), temperature, gas content within and width of the area of low pressure. Recorded the presence of eddies and their dynamics.

2. Vtoro the sensing is performed in the alignment of the drive screw. Measured: speed, width, temperature, pressure, gas content, spin and turbulence in FROM. Determines the direction FROM the presence and dynamics of eddies, the presence of PB in the alternation of areas of high pressure.

3. The third sensing is carried out for the propeller in place of the maximum velocity FRI and FROM (X/D≅20). Measured: width of areas of high pressure, the first half FROM the border with PT, PT, and the second boundary FRI FROM, the second half FROM areas of high pressure. Measured: temperature, pressure, spin and the gas content in FROM, and FRI. Defined: PB, speeding PT over speed FROM, the fact of the fence screw predominantly upper layers of the medium, the direction FROM PT and the Doppler effect.

4. The fourth sensing is performed in place of the equality of the velocities of the PT and OT (X/D≅130). Measured and determined parameters, similar p.3. Additionally, it defines the width of the Central region of high pressure, is confirmed by the approximate equality of the velocities FRI and FROM and installed the dynamics of the gas content in PT and FROM.

5. Fifth sensing is carried out in the largest speeding FROM over speed PT (the place in the ARTICLE where the pressure is maximum, the center of the force field, X/D≅220). Measured and determined parameters, similar p.3. Additionally confirms the approach to the logistics of the axial velocity FRI and is determined by the nonlinearity of the RV.

6. Sixth sensing is performed at the end of the field (X/D≅310, a place where the axial velocity and PT equal to zero and the pressure is approaching the background). Measured and determined parameters, similar p.3. The method of the fourth is like the third and differs in that the sensing is given in two mutually perpendicular planes, for example in the horizontal and in the vertical (diametrically).

The fifth way is like the third and differs in that sensing on all tacks are carried out simultaneously.

Finally, note that the main defects of performance medium of the screw caused by the asymmetry of its force field: vertical or horizontal. In the case of aircraft defects can lead to disaster. A more complete knowledge of the structure of the force field propulsion helps to understand and identify measures to improve the handling characteristics of the media.

Literature

1. Bassin A.M., Miniewicz IA theory and analysis of propellers. - L.: Sudpromgiz, 1953.

2. Rosmarin O.N. Swirling jet in a cocurrent flow of liquid of the same density. Proceedings of the ABI, No. 176. - L., 1955.

3. Lies Z.B. Hydrodynamics of the propeller. - Leningrad: Sudostroenie, 1975.

4. Myasishchev VI (as amended) Physical basics of underwater acoustics. - M.: Owls. radio, 1955.

5. Pukelman V.L. fundamentals of theory of the ship. - Leningrad: Sudostroenie, 1977.

6. Fediaevsky KK and other Hydromechanics. - L.: Cadastro the tion, 1968.

7. Bradshaw P. Introduction to turbulence and its measurement. - M.: Mir, 1974.

8. Monin A.S.,. Ozmidov W. Ocean turbulence. - L.: Gidrometeoizdat, 1981.

9. Neiman LR, Kalantarov P.L. Theoretical foundations of electrical engineering. part 2 (Theory of AC circuits). - M.-L.: Gosenergoizdat, 1959.

10. Pashukov E.B. Copyright certificate №146413 from 28.09.1979.

11. Pashukov E.B. Copyright certificate №277014 from 22.03.1982.

12. Pashukov E.B. Patent No. 2282327 from 18.11.1991. The way to detect a long shipboard internal waves.

13. Pamukov E.B. Patent No. 2281879 from 06.04.2004. Device to improve the hydrodynamic characteristics of the propeller (options).

14. Pashukov E.B. Application for invention No. 2004135662 from 05.12.2004. The way to restore the lifting force of the air screw (options and device for its implementation (options).

15. Pashukov E.B. Application for invention No. 2005106495 from 09.03.2005. Method and device for the detection of vortex formation above (before) jet aircraft (options).

16. Pashukov E.B. Application for invention No. 2004115775 from 24.05.2004. The method and apparatus of improving the aerodynamic characteristics of the propeller (options).

1. The way to define the structure of the force-field of the jet, including the creation of a field during the rotation of the screw and moving the carrier, the measurement of the main characteristics is istic field and background using imaging means and the registration field optical and television equipment, wherein the speed of rotation of the screw set, including obtaining and maintaining the direct current (FRI) greatest number of imaging component registration field produced in one of two mutually perpendicular planes, for example, in a horizontal or in a vertical, transverse visual scanning display fields produce from beginning to end or Vice versa, in characteristic locations, determining the dipole field structure; scanning before screw, fix the presence of eddies, their formation, movement, development, disappearance and synchronicity, fix boundary layer on the case of media, measure its width and its change downstream, qualitatively determine the degree of turbulence layer; scanning the target drive screw, fix the specified parameters and reverse flow (FROM), measure its width, speed, spin and turbulence; scanning for the propeller in place of the maximum velocity FRI and fix nasal diverging waves (NRW), measure their length, fix ON, FRI and boundaries between them, they measure width, axial velocity, spin, beating of PT in, calculate the ratio of the speeds and record the change in the angle expansion cocurrent flow (ST); scanning for VI is that in place of the equality of the velocities of the PT and ot, record with the same settings, no beating, areas of high pressure and the divergence angle of the ARTICLE; scanning for the propeller in place of the maximum speed FROM over speed FRI, fix similar options, beats FROM on FRI, diverging waves ARTICLE, RUST, areas of high pressure, divergence angle and the nonlinearity of the RV; scanning for a screw in place of disappearance FROM the record and measure PB, areas of high background pressure; at each scanning coordinates of the analyzed area of the field relative to the center of the screw.

2. The method according to claim 1, characterized in that the recording and scanning force fields screws are produced in two mutually perpendicular planes, for example, in the horizontal and in the vertical.

3. The way to define the structure of the force-field of the jet, including the creation of a field during the rotation of the screw and moving the carrier, the measurement of the main characteristics of the background and field meters, placed on the media, moving lines that are parallel in space and sequential time across the field with embedded sensors, characterized in that the trajectory of the sensing field passes through its characteristic places of determining the dipole field structure and located in one of two mutually perpendicular planes, for example, in a horizontal or ve is vertical, from the beginning of the field to the end or Vice versa, with the least exposure to the field of media and measuring equipment on the pitch of the screw, when the sensing measures the average and pulsation of the pressure, velocity, axial, circumferential and radial, temperature, salinity, density and gas content, pressure values set the width of the areas of low and high pressure, they belong to a cocurrent flow (ST) or diverging waves (PB), the average axial velocities determine the width of the first half of the reverse current (a), the width of the direct current (DC) and the width of the second half, the values of the pulsation velocity is set the width of the border between ot and PT and the length of the other turbulent areas, according to the average values of temperature, salinity or density and compared with the background value on the same horizon determine the fence screw predominantly upper layers of the medium and the vertical movement of the parts of the ARTICLE and PB, the average circumferential and radial velocities to determine the amount of twist and the magnitude of the centrifugal force FR and, pulsation values of radial velocities determine beating on the border of PT and ot, according to the average values of the measuring gas content establish his presence and dynamics in PT and ot, average pressure control horizon RA is the position of the probes, and time values have a "binding" of the measured parameters to a motion sensing and toward the center of the screw; probing before screw, determined FROM the average speed, width, degree of twist and turbulence, the presence of eddies and area of low pressure in the boundary layer on the body of the carrier screw determine the average speed, width, and degree of turbulence; probing the target drive screw, determined FROM similar settings; probing for the propeller in place of the maximum speed, and FRI, determine in RV width of areas of high and low pressure and their intermittency, OT, PT and determine the average speed, width, degree of twist and turbulence and width of areas of low pressure the magnitude of centrifugal forces, the speed ratio of the PT and ot, the gas content and temperature PT, set the fence screw predominantly upper layers of the medium, the width of the border and beating; probing in place of the equality of the velocities FROM and FRI determine these parameters, the width of the section of the ARTICLE, where the pressure difference from the background a minimum, establish the absence on the border of beating the presence of vertical movement of the direct current, the Doppler effect the diverging waves and determine the width of the field; probing for the propeller in place of the maximum speed reverse flow over speed direct, determined by the t of these parameters and establish a presence on the border of beating sent from reverse currents in a direct, exceeding the specified current speed, the minimum speed of the direct current or the lack of education on the axis of the cocurrent flow area of high pressure and the nonlinearity of the diverging waves; probing for a screw in the end of the field, measure these parameters and establish the absence of currents or the minimum speed reverse flow, no beating, education-axis cocurrent flow, areas of low or background pressure and measure the length of the field.

4. The method according to claim 3, characterized in that the sensing fields of the screw is held in two mutually perpendicular planes, for example, in the horizontal and in the vertical.

5. The method according to claim 3, characterized in that the sensing is performed simultaneously on all lines.



 

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EFFECT: simplified method.

4 dwg

FIELD: experimental hydromechanics; designing of equipment for conducting hydrodynamic and ice searches of marine engineering facility models in model testing basins.

SUBSTANCE: proposed device includes towing trolley with frame rigidly secured on it; this frame is provided with bar which is connected with model through dynamometers and bearing plate. Dynamometers form three-support force-measuring system; they are provided in each support in form of two interconnected elastic members; one elastic member is made in form of five-rod member provided with longitudinal and lateral force sensors; it is located between two flanges. Second elastic member of dynamometer is made in form of membrane-type elastic member whose membrane is located between rigid rim and rigid central part of this member provided with threaded rod with elastic hinge mounted over vertical axis perpendicularly relative to membrane. Membrane, rim and rigid central part with threaded rod and elastic hinge are made integral. Rim of membrane elastic members is rigidly connected with one of flanges of five-rod elastic member in such way that threaded rod is located along vertical axis of support and is rigidly connected via elastic hinge with bearing plate secured on model. Membrane is provided with resistance strain gages forming vertical force measuring bridge. Second flange of each five-rod member is connected with additional bearing plate secured on bar.

EFFECT: enhanced accuracy of measuring forces and moments.

3 dwg

FIELD: the invention refers to experimental hydrodynamics and may be used for definition of the resistance of small objects to a running flow at tests.

SUBSTANCE: the arrangement is fulfilled in the shape of a grate with the width Bt. and the height ht, deepened at the height T formed by rods with a step ▵ fixed in the supporting contour and is located at a certain distance in front of the tested object. At that it is installed with possibility of independent displacement relatively to the tested object and is fastened on the object and/or the body or probably on the bodies moving together with the tested object relatively to the test gondola. It is also may be formed by a system of private turbulators fulfilled in the shape of grates with a different size of cells, with possibility of their independent displacement relatively to each other including the fastening on different bodies and located primary in-series. The private turbulators may be fulfilled in the shape of grates particularly with different main direction of the rods of the grate. The mode is in locating the turbulator in front of the tested object with possibility of independent displacement relatively to the tested object and fastening on the object and/or on the body probably on the bodies moving together with the tested object particularly to test gondola. At that the position of the turbulator relatively to the tested object particularly the distance and displacement relatively to the tested object and also deepening and probably dimensions are chosen on the basis of comparison of results of the trial run of tarring of objects of different scales.

EFFECT: possibility of investigating of small models and revelation of the influence of resistance of the surface of the model.

6 cl, 3 dwg

FIELD: hydrodynamics.

SUBSTANCE: invention refers to experimental hydrodynamics, hydrodynamics and aerodynamics of airscrew and can be used in shipbuilding and aircraft building. Method includes force field created by airscrew rotation and carrier moving, use of visualising facilities and field structure registration by optical equipment. Thus airscrew rotary speed is established assuming production and stream maintenance of visualising facilities. Field is registered by scanning in two transversely-spaced planes, i.e. horizontal and vertical, in front of, and behind, the airscrew. Thus boundary layer, turbulence areas, increased and decreased pressure areas, airscrew expansion angles, and whole flow structure are showed.

EFFECT: high-accuracy picture of airscrew propeller environment flow.

5 cl, 16 dwg

FIELD: transportation.

SUBSTANCE: test stand for amphibious vehicles has basin with entrance and exit ramp, side walls, road, ramp and basin borders. From both sides of exit ramp pits are made in which ends of tubular shaft are embedded. Parallel arms-brackets of sheet metal are attached to the shaft equally spaced from axis. Between attached arms-brackets, spacer pipe is preliminary embedded on shaft which pipe has rectangular pawl with holes on both sides. By means of these holes the pipe is attached to captivating sheet located on symmetry axis of exit ramp. At the end of arms-brackets with lugs, cylinder is attached on axis. This cylinder is made along generator of curve corresponding to curve of vehicle front bumper. Tube rings with pawls are put on shaft ends. The pawls are fixed on pit floors. Spheroidal flanges are fixed on shaft ends to which flanges arms are attached, with brought-out from pits ends having lugs, and pneumatic cylinders are attached to arms from two sides.

EFFECT: reduction of scope of work during test stand construction and provides getting true data about capability of vehicle to move over water surface on tired wheels.

2 dwg

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