SU23114A1 - Device for hydrodynamic testing of models - Google Patents

Description

The proposed device is intended for hydro / dynamic testing of models of ships, submarines and flying boats, aircraft floats, propellers, and t.

In the schematic drawing of FIG. 1, a front view of the device with a horizontal axis of rotation of the pool; fkg 2 - the same, in a vertical section; Fig. 3 is a top view of the device with a vertical; guy axis of rotation of the pool; Fig, 4 - the same, in vertical section.

The device consists of an annular basin 1, fortified, for durability by trusses 5. Axis 2 at the height of the basin can be horizontal (Fig. 1 to 2) or vertical (Fig. 3 and 4). / {l of the installation of the model and measuring devices is designed stationary platform b, on which there is also a klbi .. about 4 l /. the observer

f / f /: The rotation of the basin 1 cod; porridge:: .-; jicM LIQUID 3 under the action of the center of obstruction forces caused by its friction against the walls, is located on the periphery of the basin. When the axis of rotation is horizontal, the liquid forms the surface of a regular cylinder, the axis of which lies slightly above axis 2

pool (Fig. 2). With a vertical axis of rotation, the surface of the liquid is a paraboloid (Fig 4).

The test model, installed outside the rotating system on the corresponding instruments showing the hydrodynamic pressure, is immersed in a sitting room 3. The model doesn’t (; and the liquid runs onto it just like an air stream moves around the stationary model of the aircraft.

Due to the fact that the fluid moves in a circle, the model also needs to be curved along an arc of a corresponding radius. In addition, when testing, it is necessary to take into account that, in the proposed installation, a centrifuge acts beyond the force of gravity on the liquid.

The described device is intended). 1) to determine the hydrodynamic pressure for different diving models, at different differents and speeds, 2) to distribute pressures on the bottom of the model, which is very important for strength calculation and choice of forms, 3) to determine the forces friction of the water at the outlet of the diver on the side, 4) to determine the stability of the path and 5) to test models of the screws, etc.,

As advantages of the described device over a conventional hydrochannel with a trolley, it is indicated that a constant flow of fluid in the pool makes it possible to test models for as long as necessary, while tests in the channels are instantaneous on automatic instruments. Further, due to the fact that the measuring instruments are fixed, they are not affected by the forces and inertia of their individual parts, which ensures greater accuracy of the readings. In addition, the proposed device makes it possible to simultaneously test several models depending on the pool radius and to obtain high fluid velocities for testing different types of tanks.

The following is an approximate calculation of a device with a vertical axis of rotation of the pool (Fig. 3 H 4).

The task. Model seaplane, scale-0,1.

Decision. The flow rate according to the similarity formula will be equal to 12 MICCK. To eliminate the influence of vessel walls and reduce the curvature, a cylindrical pool with a radius of R 5 "and a height of H 1.5 m is selected. The amount of water is also chosen from the calculation to eliminate the influence of the vessel wall. It is known that the surface of the stream should be 15 times the width of the model, and the distance to the bottom is 35 times the immersion depth of the model. The volume V of water filled will be expressed as

V (R -r ;-) H 3.14 (25-16) 1.5

 42 m

where r 4 is the average radius of the surface of revolution.

C. The speed of the stream is 12 m1 sec, the number of revolutions of the basin is 30 ~ 6 msh.

The rotating fluid forms a paraboloid: g Z, where and 3.14 is the angle

vessel velocity, Z is the height of the paraboloid and g is the acceleration of the force of gravity.

On the basis of the equality between the volume of poured water and the volume obtained after rotation of the basin, we define rj, gi, Z and a ° (Fig, 4),

V - (g + r2) n

25- | , 25-Z- (Z-l, 5)

g - 2 “7

19.6 17.. i-73 10

r, 2 gz.2 (Z-l, 5) -H5.v2

™ Gg 10 4.03

 4.1

tg "

9.81

From here:

, 75. “G, 4.18 m G2 3.88 m

a °

The resulting rj, g, Z and "are quite suitable for testing models; at higher speeds, even better conditions will be obtained. It is advisable to take the pool's radius as large as possible: 8-10 metros.

The subject matter of the invention.

A device for hydrodynamic testing of models, characterized by the use of an annular basin for the movement of the liquid 3 filling it, in order to form a constant annular flow, the test chambers with stationary dynamometers are located along the inner circumference.

itiji .ii..and Ts11mvd1zd-tsd-,: 11 "and Yes to the author's testimony V. figl. G. Frolova 28114 figure 2.

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