Towing tank PIV test model forced constraint device and use method

Abstract

The invention relates to a towing tank PIV test model forced restraint device and a use method, the towing tank PIV test model forced restraint device comprises a test ship model, a plurality of ship model deck connecting plates are arranged on the test ship model, a model forced restraint device is installed on each ship model deck connecting plate through a ship model connecting seat, and the model forced restraint devices are connected with a test platform; the structural strength and rigidity are good, and the model is dragged, and the attitude stability of the model is kept; the two sets of devices are cooperatively used, the position of the model can be quickly adjusted in three degrees of freedom in the vertical direction, the transverse direction and the longitudinal direction, the test requirements of various trim angles of the ship model can be met in real time by releasing the connecting seat with the degree of freedom limitation in the trim aspect, and the working intensity of operators in the preparation stage is reduced; the connection strength between the device and the ship model is further enhanced through a reference waterline installation method, the stability of the ship model in a water pool can be guaranteed in the test preparation stage, and personnel can conveniently fix the device and the ship model.

Description

Technical Field

[0001] The invention relates to the technical field of ship dynamics test devices, and in particular to a towing tank PIV test model forced restraint device and a use method thereof. Background Art

[0002] At present, the PIV flow field test in deep-water towing tanks is mainly based on the test method of installing the system on the vehicle. The shore-based test method has almost been abandoned, and the flow field test plan is mainly formulated around the Stereo-PIV (including 2 cameras) system based on the working principle of binocular imaging. The laser output by the Stereo-PIV system is in the form of sheet light.

[0003] The researchers are very interested in the flow field distribution around the ship model body, appendages, and especially the propeller. In the towing tank test scenario, the speed along the towing direction (or flow direction) is much greater than the speed in the other two directions. Considering the structural stiffness of the PIV test system and the degree of interference to the test area, the laser part and the camera system of the Stereo-PIV system are integrated in the same rigid structure, resulting in the output sheet laser being perpendicular to the towing direction. In order to ensure that there is a suitable pixel offset value on the camera photosensitive element, it is necessary to control the shooting time interval between two adjacent frames not to be too small, otherwise the peak locking phenomenon will occur, making it difficult to identify the displacement of the particle group in the previous and next frames. The large flow velocity will also cause the tracer particles to leave the laser illuminated area when the second frame is taken. Therefore, the velocity field obtained by cross-correlation calculation of the original pictures of the tracer particle distribution in the adjacent two frames will have more velocity bad points due to the loss of particle crossing. From a statistical point of view, multiple groups of pictures can be taken continuously and the calculated velocity field can be averaged to obtain better flow field results. However, the above-mentioned method of averaging the sampled multiple groups of data samples requires the model to be in a stable state during the test. In addition, PIV flow field tests in towing tanks are generally carried out under still water conditions. Researchers focus on the target flow field distribution at typical speeds in still water. The design / structural draft waterline of the ship model is the intersection line between the target ship at rest in still water and the water surface. The ship model has posture changes such as bow raising / bow burying in the moving state. The waterline at this time is different from the waterline when the ship model is at rest. Therefore, when conducting flow field tests, the ship model's posture needs to be adjusted to the posture during free navigation.

[0004] In the existing technology, there are few towing tanks capable of conducting three-dimensional PIV flow field tests on ship models, and most of them are commercial tanks with limited public information. There are mainly two ways to constrain the model:

[0005] 1. Adopt the drag meter developed by CUSSONS Company in the UK for the resistance self-propulsion test task. There is a set of pneumatically controlled fixtures on this drag meter. Use this fixture to drive the ship model to run at a set speed, and cooperate with the relevant navigation devices in the resistance self-propulsion test to restrict surge and yaw, etc., so that the ship model is in a free state in the two attitudes of heave and trim, and automatically reaches a stable balance. However, the pneumatic brake device adopted in this scheme is affected by the poor stiffness of the pneumatic system. After each braking, the clamping point of the fixture has a physical position deviation relative to the trailer, resulting in a position deviation between the actual measurement surface of the flow field and the expected measurement surface, losing the meaning of flow field measurement;

[0006] 2. Before launching, draw the waterline corresponding to the free state at the set speed on the surface of the ship model. Use wooden boards to forcibly bind the ship model and the trailer test platform. During the fixing process, adjust the fixing method of each wooden board according to the drawn waterline to align the waterline with the water surface. The disadvantage of this method is that the stiffness of the wooden board is poor, and there is a certain degree of deformation during towing, which will cause changes in the model attitude. In addition, there are many wooden boards installed on site, and the installation position of each wooden board needs to be strictly controlled to ensure the alignment of the waterline with the water surface of the pool, bringing a large amount of work and high difficulty. Summary of the Invention

[0007] In view of the problems of low efficiency, large workload and poor structural stability in the existing model attitude adjustment methods in the PIV three-dimensional flow field test in the deep water towing tank in the above-mentioned existing production technology, and the effective measurement area of the existing commercial Stereo-PIV system is solidified at the design stage, with almost no adjustment space, so there is a problem of matching the measured area of the model and the measurable area of the PIV system. Therefore, the applicant provides a forced constraint device and a use method for the PIV test model in the towing tank, so that it has relatively rich attitude constraint functions, an efficient and simple implementation process and reliable ship model attitude maintenance characteristics.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A forced constraint device for a PIV test model in a towing tank, comprising a test ship model. A plurality of ship model deck connecting plates are arranged on the test ship model. A model forced constraint device is installed on a single ship model deck connecting plate through a ship model connecting seat. The model forced constraint device is connected to the test platform;

[0010] The structure of the model forced constraint device is as follows: it includes a slider rail and a gear rail arranged at intervals. The slider rail is seated on the test platform slide rail and slides along the test platform slide rail. The gear rail is seated on the test platform base, and a rack of the test platform is installed on the test platform base. There are horizontally moving slide rails distributed at intervals between the slider rail and the gear rail. Clamping devices are installed at one end of the slider rail and both ends of the gear rail respectively; the slider rail, the gear rail and the two horizontally moving slide rails form a quadrilateral structure. A horizontally moving drive mechanism is installed outside one of the horizontally moving slide rails. A translation frame is installed in cooperation with the two horizontally moving slide rails. A lifting rod is installed inside the translation frame. A top plate is fixed on the top surface of the translation frame. A motor is installed on the top plate. The output end of the motor is connected to a worm and worm gear mechanism. The output shaft of the worm and worm gear mechanism passes through the top plate and is locked with the lifting rod. The bottom of the lifting rod is fixed to the ship model connecting seat.

[0011] Its further technical solution lies in:

[0012] The clamping device can tightly hold the test platform slide rail and the test platform base, thereby locking the entire set of model forced constraint device on the test platform.

[0013] A longitudinally moving drive mechanism is inserted into the gear rail. The core drive component, the cylindrical gear, is inside the gear rail and meshes with the rack.

[0014] The output end of the motor is connected to the worm and worm gear mechanism through a coupling; a backing plate is installed on the top plate to balance the height difference between the motor and the worm and worm gear mechanism.

[0015] Two vertical moving sliders are installed on each side of the translation frame and fixed with fasteners. The vertical moving slide rails are fixed on both sides of the lifting rod with fasteners. A large nut is fixed at the top of the lifting rod. The output end of the worm and worm gear mechanism and the large nut cooperate to drive the lifting rod to move vertically. The four vertical moving sliders and the two vertical moving slide rails cooperate to play a role in moving guidance.

[0016] A first pointer is installed on the lifting rod, and a vertically arranged scale is pasted on the translation frame. They can be used together to display the vertical position of the lifting rod.

[0017] The main horizontal cross beam and the secondary horizontal cross beam are respectively fixed on the slider rail and the gear rail with fasteners. A horizontally moving slide rail is laid on the upper surfaces of the main horizontal cross beam and the secondary horizontal cross beam. Horizontal moving sliders are fixed on both sides of the translation frame. The horizontal moving sliders cooperate with the horizontally moving slide rails to play a role in sliding guidance.

[0018] Both the main horizontal cross beam and the secondary horizontal cross beam adopt I-beam structures.

[0019] The installation structure of the lateral movement driving mechanism is as follows: The smaller-diameter end of the driving lead screw is first inserted into the first thrust ball bearing, and then passes through the through-hole of the main lateral cross beam. The first thrust ball bearing is embedded in the mounting seat to play a role of rotational support. At the penetrated part, the second thrust ball bearing and the retaining ring body are installed. The aperture of the through-hole of the main lateral cross beam is smaller than the diameters of the first thrust ball bearing and the second thrust ball bearing. The first thrust ball bearing and the second thrust ball bearing are separated by the main lateral cross beam. A small section of fine thread is cut on the smaller-diameter end of the driving lead screw. The second thrust ball bearing and the retaining ring body are tightly fitted to the main lateral cross beam through a small round nut. The handle is installed at the end to facilitate the rotation of the driving lead screw. The nut is installed upside down on the translation frame. The larger-diameter end of the driving lead screw is cut with a coarse thread for cooperation with the nut. By rotating the handle, the driving lead screw drives the nut, and the translation frame can move laterally under the guiding action of the lateral movement slider and the lateral movement slide rail. Two limit blocks are installed on each lateral movement slide rail, and these two limit blocks are distributed on both sides of the translation frame. When the translation frame moves laterally to a predetermined position, the lateral position of the translation frame is locked by using fasteners and limit blocks.

[0020] A usage method of a forced constraint device for a towing tank PIV test model includes the following processes:

[0021] Draw a draft line of the test ship model in the free navigation state on the horizontal platform, and draw a reference draft line about 1 cm below this draft line;

[0022] The forced constraint device is located on the trailer test platform. The slider rail and the gear rail cooperate with the slide rail bar and the gear bar on the test platform to play a guiding role. By rotating the cylindrical gear, the forced constraint device can slide along the slide rail bar or the gear rail bar under the interaction of the gear and the gear bar. A locking component is provided to keep the position of the forced constraint device and the slide rail bar or the gear rail bar unchanged;

[0023] The lifting rod is fixed to the ship model through the model connecting seat. The model connecting seat releases the trim constraint and can adapt to different trim angle requirements of the ship model in the free state;

[0024] The lifting rod is driven to move vertically by the motor and the worm and worm gear mechanism;

[0025] Iron weights are placed in the test ship model until the reference water line is flush with the water surface. Adjust the heights of the lifting rods of the two forced constraint devices above, press down the test ship model to make the free navigation state water line flush with the water surface, and then connect the model connecting seat and the test ship model to lock the heave and trim postures of the test ship model.

[0026] The beneficial effects of the present invention are as follows:

[0027] The structure of the present invention is compact and reasonable, and it is convenient to operate. By adopting a relatively large amount of steel structure design, it has good structural strength and stiffness, and has good performance in towing the model and maintaining the attitude stability of the model. When the two sets of devices are used in cooperation, the position of the model can be quickly adjusted in the three degrees of freedom of vertical, horizontal and longitudinal directions. The connecting seat with unrestricted freedom in the trim aspect can meet the test requirements of various trim angles of the ship model in real time, reducing the work intensity of the operator in the preparation stage. The proposed installation method of the reference waterline further strengthens the connection strength between the device and the ship model, and can ensure the stability of the ship model in the water tank during the test preparation stage, facilitating the personnel to fix the device and the ship model.

[0028] The present invention efficiently realizes the position adjustment of the ship model in the three directions of horizontal, vertical and longitudinal through mechanical mechanisms and electrification devices, and the model connecting seat in the form of a "see-saw" structure can be conveniently and quickly fixed on the model deck surface with trim changes.

[0029] The forced restraint device of the present invention adopts a mechanical structure, with high system strength and stiffness, and has a certain position locking ability in three directions, so that the model attitude maintains good stability during the test.

[0030] Based on the installation method of the reference waterline for shallow draft, the present invention increases the vertical acting force between the ship model and the lifting rod of the forced restraint device, improves the stability of the ship model in the water tank during the installation stage, facilitates the installation personnel to walk inside the ship model to carry out positioning and installation work, reduces the operation difficulty and improves the operation efficiency.

[0031] The lateral movement function of the model forced restraint device of the present invention enables the Stereo-PIV system with fixed measurement distance to be applied to ship models of different sizes and different measurement areas (propeller disk surface, ship appendages), that is, it expands the test range of the existing PIV system while restraining the model.

[0032] The present invention is applicable to attitude control of the target ship model according to the expected value during the vehicle-mounted PIV flow field test in a deep water towing tank, and enables the target measurement area to fall within the best test range of the PIV system, as well as the method for adjusting the heave (vertical oscillation) and trim (pitching) attitudes of the ship model and firmly connecting with the ship model. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is an application diagram of the model forced restraint device of the present invention.

[0034] Figure 2 It is a structural schematic diagram of the model forced restraint device of the present invention.

[0035] Figure 3 It is a top view of the model forced restraint device of the present invention.

[0036] Figure 4 This is the front view of the model forced constraint device of the present invention.

[0037] Figure 5 This is the side view of the model forced constraint device of the present invention.

[0038] Figure 6 This is the front view of the transverse movement driving lead screw in the model forced constraint device of the present invention.

[0039] Figure 7 This is the structural schematic diagram of the transverse movement driving mechanism in the model forced constraint device of the present invention.

[0040] Figure 8 This is the front view of the main transverse crossbeam in the model forced constraint device of the present invention.

[0041] Figure 9 This is the rear view of the main transverse crossbeam in the model forced constraint device of the present invention.

[0042] Figure 10 This is the top view of the longitudinal movement mechanism in the model forced constraint device of the present invention.

[0043] Figure 11 This is the bottom view of the longitudinal movement mechanism in the model forced constraint device of the present invention.

[0044] Figure 12 This is the front view of the extension rod in the model forced constraint device of the present invention.

[0045] Figure 13 This is the side view of the extension rod in the model forced constraint device of the present invention.

[0046] Figure 14 This is the assembly schematic diagram of the longitudinal movement driving components in the model forced constraint device of the present invention.

[0047] Figure 15 This is the assembly schematic diagram of the key components of the longitudinal movement in the model forced constraint device of the present invention.

[0048] Wherein: 1. Test platform; 2. Ship model deck connecting plate; 3. Test ship model; 4. Clamping device; 5. Slide block rail; 6. Gear rail; 7. Lateral movement slide rail; 8. No. 7 hexagon socket head cap screw; 9. No. 2 hexagon socket head cap screw; 10. Motor; 11. Ship model connecting seat; 12. Coupling; 13. Worm and worm gear mechanism; 14. Base plate; 15. Translation frame; 16. Big nut; 17. Vertical movement slide rail; 18. Vertical movement slide block; 19. No. 3 hexagon socket head cap screw; 20. Scale; 21. No. 5 hexagon socket head cap screw; 22. First pointer; 23. Lifting rod; 24. Second pointer; 25. Sub-lateral cross beam; 26. No. 6 hexagon socket head cap screw; 27. Main lateral cross beam; 28. No. 10 hexagon socket head cap screw; 29. No. 8 hexagon socket head cap screw; 30. Lateral movement slide block; 31. Limit block; 32. No. 4 hexagon socket head cap screw; 33. Lateral movement driving mechanism; 34. Longitudinal movement driving mechanism; 35. No. 1 hexagon socket head cap screw;

[0049] 101. Test platform slide rail; 102. Test platform base; 103. Rack;

[0050] 1101. Mounting plate; 1102. Cotter retaining ring; 1103. A-type split pin; 1104. Cotter pin;

[0051] 3301. Driving lead screw; 3302. Nut; 3303. No. 9 hexagon socket head cap screw; 3304. Retaining ring body; 3305. No. 1 thrust ball bearing; 3306. No. 2 thrust ball bearing; 3307. Small round nut; 3308. Handle; 3401. Bearing cover; 3402. Shaft head fixing plate; 3403. Deep groove ball bearing; 3404. Extension rod; 3405. Cylindrical roller bearing; 3406. Cylindrical gear; 3407. Spline. Specific embodiments

[0052] The following combines with the attached drawings to illustrate the specific embodiments of the present invention.

[0053] As Figures 1 - 15 shown, the forced constraint device for the towing tank PIV test model of this embodiment includes a test ship model 3. A plurality of ship model deck connecting plates 2 are arranged on the test ship model 3. The model forced constraint device is installed on a single ship model deck connecting plate 2 through a ship model connecting seat 11, and the model forced constraint device is connected to the test platform 1;

[0054] The structure of the model forced constraint device is as follows: it includes a slider rail 5 and a gear rail 6 arranged at intervals. The slider rail 5 is seated on the test platform slide rail 101 and slides along the test platform slide rail 101. The gear rail 6 is seated on the test platform base 102, and a rack 103 of the test platform 1 is installed on the test platform base 102. There are laterally moving slide rails 7 distributed at intervals between the slider rail 5 and the gear rail 6. Clamping devices 4 are respectively installed at one end of the slider rail 5 and both ends of the gear rail 6; the slider rail 5, the gear rail 6 and the two laterally moving slide rails 7 form a quadrilateral structure. A laterally moving drive mechanism 33 is installed outside one of the laterally moving slide rails 7. A translation frame 15 is cooperatively installed on the two laterally moving slide rails 7. A lifting rod 23 is installed inside the translation frame 15. A top plate is fixed on the top surface of the translation frame 15, and a motor 10 is installed on the top plate. The output end of the motor 10 is connected to a worm and worm gear mechanism 13. The output shaft of the worm and worm gear mechanism 13 passes through the top plate and is locked with the lifting rod 23. The bottom of the lifting rod 23 is fixed to the ship model connecting seat 11.

[0055] The clamping device 4 can tightly hold the test platform slide rail 101 and the test platform base 102, thereby locking the entire set of model forced constraint devices on the test platform 1.

[0056] A longitudinally moving drive mechanism 34 is inserted into the gear rail 6. The core drive component, the cylindrical gear 3406, is inside the gear rail 6 and meshes with the rack 103.

[0057] The output end of the motor 10 is connected to the worm and worm gear mechanism 13 through a coupling 12; a backing plate 14 is installed on the top plate, and the backing plate 14 is used to balance the height difference between the motor 10 and the worm and worm gear mechanism 13.

[0058] Two vertical moving sliders 18 are respectively installed on both sides of the translation frame 15 and fixed with fasteners. The vertical moving slide rails 17 are fixed on both sides of the lifting rod 23 with fasteners. A large nut 16 is fixed at the top of the lifting rod 23. The output end of the worm and worm gear mechanism 13 and the large nut 16 cooperate to drive the lifting rod 23 to move vertically. The four vertical moving sliders 18 and the two vertical moving slide rails 17 cooperate to play a role in moving guidance.

[0059] A first pointer 22 is installed on the lifting rod 23, and a vertically arranged scale 20 is pasted on the translation frame 15. The two can be used in combination to display the vertical position of the lifting rod 23.

[0060] The main transverse beam 27 and the secondary transverse beam 25 are respectively fixed on the slider rail 5 and the gear rail 6 through fasteners. A laterally moving slide rail 7 is laid on the upper surfaces of both the main transverse beam 27 and the secondary transverse beam 25. Transverse moving sliders 30 are fixed on both sides of the translation frame 15. The transverse moving sliders 30 cooperate with the laterally moving slide rails 7 to play a role in sliding guidance.

[0061] Both the main transverse beam 27 and the secondary transverse beam 25 adopt I-beam structures.

[0062] The installation structure of the transverse movement driving mechanism 33 is as follows: The smaller-diameter end of the driving lead screw 3301 is first inserted into the first thrust ball bearing 3305, and then passes through the through-hole of the main transverse beam 27. The first thrust ball bearing 3305 is embedded in the mounting seat to play a role of rotational support. At the penetrated part, the second thrust ball bearing 3306 and the retaining ring body 3304 are installed. The diameter of the through-hole of the main transverse beam 27 is smaller than the diameters of the first thrust ball bearing 3305 and the second thrust ball bearing 3306. The first thrust ball bearing 3305 and the second thrust ball bearing 3306 are separated by the main transverse beam 27. A small section of fine thread is cut on the smaller-diameter end of the driving lead screw 3301. The second thrust ball bearing 3306 and the retaining ring body 3304 are tightly fitted to the main transverse beam 27 through the small round nut 3307. The handle 3308 is installed at the end to facilitate the rotation of the driving lead screw 3301. The nut 3302 is installed upside down on the translation frame 15. The larger-diameter end of the driving lead screw 3301 is cut with a coarse thread to cooperate with the nut 3302. By rotating the handle 3308, the driving lead screw 3301 drives the nut 3302, and the translation frame 15 can move horizontally under the guiding action of the transverse movement slider 30 and the transverse movement slide rail 7. Two limit blocks 31 are installed on each transverse movement slide rail 7, and these two limit blocks 31 are distributed on both sides of the translation frame 15. When the translation frame 15 moves horizontally to the predetermined position, the transverse position of the translation frame 15 is locked by using fasteners and the limit blocks 31.

[0063] The specific structure and functions of the forced restraint device for the towing tank PIV test model of the present invention are as follows:

[0064] Figure 1 It is an application diagram of the model forced restraint device. The X direction is the longitudinal direction, the Y direction is the transverse direction, and the Z direction is the vertical direction. Among them, the test platform 1 is connected to the test ship model 3 through the ship model connection seat 11 and the ship model deck connection plate 2. The rack 103 of the test platform 1 is installed on the test platform base 102, and the test platform slide rail 101 and the test platform base 102 are respectively installed on both sides of the test platform 1.

[0065] As Figures 2 - 5 shown, the slider rail 5 of the model forced restraint device is seated on the test platform slide rail 101 and can slide along the test platform slide rail 101. The test platform slide rail 101 plays a guiding role for the slider rail 5; the gear rail 6 is seated on the test platform base 102.

[0066] The clamping device 4 is closely attached to one end of the slider rail 5 and both ends of the gear rail 6 through the first hexagon socket head cap screw 35. The clamping device 4 can tightly hold the test platform slide rail 101 and the test platform base 102, thereby locking the entire model forced constraint device on the test platform 1.

[0067] The longitudinal movement driving mechanism 34 is inserted into the gear rail 6. The core driving component, the cylindrical gear 3406, is inside the gear rail 6 and meshes with the rack 103. One end penetrates the gear rail 6 and is supported by the shaft head fixing plate 3402 fixed outside the gear rail 6. The other end is extended by using the spline 3407 and the extension rod 3404. The extension rod 3404 is sleeved with a deep groove ball bearing 3403, and the shaft rod of the cylindrical gear 3406 is sleeved with a cylindrical roller bearing 3405. The above parts are inserted into the bearing cover 3401 fixed on one side of the gear rail 6. The operator rotates the extension rod 3404 to make the cylindrical gear 3406 roll along the rack 103, and the test platform slide rail 101 guides the slider rail 5, so that the entire model forced constraint device can move longitudinally.

[0068] The motor 10 drives the worm and worm gear mechanism 13 through the coupling 12. The worm and worm gear mechanism 13 is installed on the top of the translation frame 15 through the second hexagon socket head cap screw 9 and the backing plate 14. The backing plate 14 is used to balance the height difference between the motor 10 and the worm and worm gear mechanism 13.

[0069] Two vertical movement sliders 18 are installed on each side of the translation frame 15 and fixed with the third hexagon socket head cap screw 19; the vertical movement slide rail 17 is fixed on both sides of the lifting rod 23 with the fourth hexagon socket head cap screw 32; the fifth hexagon socket head cap screw 21 fixes the large nut 16 on the top of the lifting rod 23; the output end of the worm and worm gear mechanism 13 cooperates with the large nut 16 to drive the lifting rod 23 to move vertically, and the four vertical movement sliders 18 and the two vertical movement slide rails 17 cooperate to play a role in guiding the movement.

[0070] The first pointer 22 is installed on the lifting rod 23, and the scale 20 arranged vertically is pasted on the translation frame 15. They can be used together to display the vertical position of the lifting rod 23.

[0071] The main transverse beam 27 and the auxiliary transverse beam 25 are horizontally fixed on the slider rail 5 and the gear rail 6 through the sixth hexagon socket head cap screw 26. The main bodies of these two beams both adopt I-beam structures, and a transverse movement slide rail 7 is laid on the upper surface of each and fixed with the seventh hexagon socket head cap screw 8; two transverse movement sliders 30 are installed and fixed on both sides of the translation frame 15 with the eighth hexagon socket head cap screw 29, and the transverse movement sliders 30 can cooperate with the transverse movement slide rail 7 to play a role in guiding the sliding.

[0072] The smaller-diameter end of the driving lead screw 3301 is first inserted into the first thrust ball bearing 3305, and then passes through the through-hole of the main transverse beam 27. The first thrust ball bearing 3305 is embedded in the mounting seat to play a role of rotational support. The second thrust ball bearing 3306 and the retaining ring body 3304 are installed at the penetrated part. The diameter of the through-hole of the main transverse beam 27 is smaller than the diameters of the first thrust ball bearing 3305 and the second thrust ball bearing 3306. Therefore, the first thrust ball bearing 3305 and the second thrust ball bearing 3306 are separated by the main transverse beam 27. A small section of fine thread is turned on the smaller-diameter end of the driving lead screw 3301. The second thrust ball bearing 3306 and the retaining ring body 3304 are tightly fitted to the main transverse beam 27 by the small round nut 3307. The handle 3308 is installed at the end to facilitate the rotation of the driving lead screw 3301. This structure can ensure that when the transverse movement driving mechanism 33 rotates, the driving lead screw 3301 only makes a rotational movement and does not have an axial displacement. Here, the second thrust ball bearing 3306 only plays a rotational role to prevent dry friction between the retaining ring body 3304 and the main transverse beam 27 when the retaining ring body 3304 rotates; the nine-point socket head cap screw 3303 reversely installs the nut 3302 on the translation frame 15. The larger-diameter end of the driving lead screw 3301 is turned with a coarse thread for cooperation with the nut 3302; when the handle 3308 is rotated, the driving lead screw 3301 drives the nut 3302, and the translation frame 15 can move horizontally under the guiding action of the transverse movement slider 30 and the transverse movement slide rail 7. Two limit blocks 31 are installed on each transverse movement slide rail 7. These two limit blocks 31 are distributed on both sides of the translation frame 15. When the translation frame 15 moves horizontally to a predetermined position, the tenth socket head cap screw 28 and the limit block 31 can be used to lock the horizontal position of the translation frame 15.

[0073] A second pointer 24 is installed on the translation frame 15, and a scale arranged horizontally is pasted on the secondary transverse beam 25. They can be used in combination to display the horizontal position of the translation frame 15.

[0074] The ship model connecting seat 11 is installed at the bottom of the lifting rod 23. The pin 1104 passes through the mounting plate 1101 and the round hole at the bottom of the lifting rod 23. The mounting plate 1101 can rotate around the pin 1104, which can meet the adjustment needs of different longitudinal angles of the ship model during the test preparation stage. Locking can be achieved in cooperation with the pin retaining ring 1102 and the A-type split pin 1103 to prevent loosening during use.

[0075] Two model forced restraint devices are fixed on the test platform 1. Iron weights are placed inside the test ship model 3 until the reference waterline is flush with the water surface. Operate the longitudinal movement drive mechanism 34 to match the positions between the ship model connecting seat 11 and the ship model deck connecting plate 2. Then control the motor 10 to adjust the heights of the lifting rods 23 of the two forced restraint devices, press down the test ship model 3, and make the free navigation state waterline flush with the water surface. Since the ship model has no yaw angle and roll angle, during the pressing process, the ship model connecting seat 11 in the free state in trim will freely adapt to the attitude of the test ship model 3. Then use screws to lock the ship model connecting seat 11 and the ship model deck connecting plate 2. Under the combined action of the two model forced restraint devices, the attitude of the test ship model 3 can be stably maintained.

[0076] Operating the lateral movement drive mechanism 33 can change the distance between the PIV device and the test ship model 3, so that the target test section on the test ship model 3 falls within the best test range of the PIV device.

[0077] Before the formal test, it is necessary to use the clamping device 4 to lock the longitudinal position of the model forced restraint device, use the limit block 31 to lock the lateral position of the translation frame 15. The worm and worm gear mechanism 13 has a certain self-locking ability. When not driven by the motor 10, the vertical position of the lifting rod 23 can still be locked.

[0078] During the actual working process, the work is completed through the following process:

[0079] (1) Draw a draft line of the target ship model in the free navigation state on the horizontal platform, and draw a reference draft line about 1 cm below this draft line;

[0080] (2) The forced restraint device is located on the trailer test platform 1. The slider rail 5 and the gear rail 6 cooperate with the slide rail strip and the gear strip on the test platform 1 to play a guiding role. By rotating the cylindrical gear 3406, under the interaction of the gear and the gear strip, the forced restraint device can slide along the slide rail strip / gear rail strip, and the locking component can keep the position of the forced restraint device and the slide rail strip / gear rail strip unchanged;

[0081] (3) The lifting rod 23 is fixed to the ship model through the model connecting seat. The model connecting seat releases the trim restraint and can adapt to different trim angle requirements of the ship model in the free state;

[0082] (4) Drive the lifting rod 23 to move vertically through the motor 10 and the worm and worm gear mechanism 13. At the same time, a slide rail and slider structure is equipped to play a guiding and stabilizing role in the vertical movement of the lifting rod 23;

[0083] (5) The motor 10, the worm and worm gear mechanism 13, and the moving lifting rod 23 are fixed on the moving platform. The moving platform can move horizontally through a lead screw - nut structure, and is equipped with a slide rail and slider structure, which plays a role in guiding and maintaining the stability of the horizontal movement of the moving platform. At the same time, a locking device is arranged on the slide rail to prevent the ship model from shifting in position under the action of hydrodynamic force;

[0084] (6) Place ballast in the ship model until the reference water line is flush with the water surface. Adjust the height of the lifting rods 23 of the above two forced restraint devices to press down the ship model so that the free - sailing water line is flush with the water surface. Then connect the model connecting seat and the ship model to lock the heave and pitch attitudes of the ship model.

[0085] The present invention efficiently realizes the position adjustment of the ship model in three directions: horizontal, vertical, and longitudinal, and realizes self - locking / manual locking in three adjustable degrees of freedom, further maintaining the adjustment effect of the device and improving the efficiency of the test preparation stage. Among them, the function of horizontally moving the ship model can make the target measurement area of the ship model fall within the best test range of the 2D3C Stereo - PIV device with limited moving ability and limited test distance, expanding the application scenario of the PIV system.

[0086] The connecting seat of the present invention connected to the ship model releases the pitch degree of freedom, which can easily meet the requirements of the forced towing flow field test for the pitch angle of the ship model in the free - sailing state, reducing the difficulty of the test preparation stage.

[0087] The present invention adopts a working scheme of two sets of devices working together to provide sufficient strength and stiffness to maintain the model attitude, and can achieve a constant ship model attitude at a relatively high towing speed.

[0088] Based on the reference water line installation method for shallow draft, the present invention uses buoyancy to strengthen the acting force between the test ship model 3 and the lifting rod 23 of the forced restraint device, enhancing the stability of the ship model in the water tank during the test preparation stage, reducing the installation difficulty of personnel, improving the operation efficiency, and strengthening the connection strength between the model and the forced restraint device.

[0089] The above description is an explanation of the present invention, not a limitation of the invention. The scope defined by the present invention is referred to the claims, and any form of modification can be made within the protection scope of the present invention.

Claims

1. A forced restraint device for a towing tank PIV test model, characterized in that: The test ship model (3) comprises a plurality of ship model deck connection plates (2) arranged on the test ship model (3), a model forced constraint device being installed on a single ship model deck connection plate (2) via a ship model connection seat (11), and the model forced constraint device being connected to a test platform (1); The structure of the model forced constraint device is as follows: it comprises a slider rail (5) and a gear rail (6) arranged at intervals, the slider rail (5) is seated on a test platform slide rail (101), the slider rail (5) slides along the test platform slide rail (101), the gear rail (6) is seated on a test platform base (102), a rack (103) of the test platform (1) is installed on the test platform base (102), a transverse moving slide rail (7) is arranged at intervals between the slider rail (5) and the gear rail (6), and a clamping device (4) is installed at one end of the slider rail (5) and at both ends of the gear rail (6); the slider rail (5) and the gear rail (6) are respectively provided with a plurality of clamping devices (4); ) and two transverse moving slide rails (7) form a quadrilateral structure, a transverse moving driving mechanism (33) is installed outside one of the transverse moving slide rails (7), a translation frame (15) is installed on the two transverse moving slide rails (7), a lifting rod (23) is installed inside the translation frame (15), a top plate is fixed on the top surface of the translation frame (15), a motor (10) is installed on the top plate, an output end of the motor (10) is connected to a worm gear mechanism (13), an output shaft of the worm gear mechanism (13) passes through the top plate and is locked with the lifting rod (23), and the bottom of the lifting rod (23) is fixed to the ship model connecting seat (11).

2. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: The clamping device (4) can tightly hold the test platform slide rail (101) and the test platform base (102), thereby locking the entire set of model forced restraint devices on the test platform (1).

3. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: The longitudinal movement driving mechanism (34) is inserted into the gear rail (6), and the core driving component cylindrical gear (3406) is inside the gear rail (6) and meshes with the rack (103).

4. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: The output end of the motor (10) is connected to the worm gear mechanism (13) via a coupling (12); a pad (14) is installed on the top plate, and the pad (14) is used to balance the height difference between the motor (10) and the worm gear mechanism (13).

5. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: Two vertical moving sliders (18) are installed on both sides of the translation frame (15) and fixed by fasteners. The vertical moving slide rails (17) are fixed on both sides of the lifting rod (23) by fasteners. A large nut (16) is fixed on the top of the lifting rod (23). The output end of the worm gear mechanism (13) and the large nut (16) work together to drive the lifting rod (23) to move vertically. The four vertical moving sliders (18) and the two vertical moving slide rails (17) work together to play a moving guide role.

6. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: A first pointer (22) is mounted on the lifting rod (23), and a scale (20) arranged vertically is attached to the translation frame (15), which can display the vertical position of the lifting rod (23) when used in conjunction.

7. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: The main transverse beam (27) and the auxiliary transverse beam (25) are respectively fixed on the slider rail (5) and the gear rail (6) by fasteners. The upper surfaces of the main transverse beam (27) and the auxiliary transverse beam (25) are both provided with a transverse moving slide rail (7). Transverse moving slide blocks (30) are fixed on both sides of the translation frame (15). The transverse moving slide blocks (30) cooperate with the transverse moving slide rail (7) for sliding guide purposes.

8. A towing tank PIV test model forced restraint device as claimed in claim 7, characterized in that: The main transverse beam (27) and the secondary transverse beam (25) both adopt an I-beam structure.

9. A towing tank PIV test model forced restraint device as claimed in claim 1, characterized in that: The installation structure of the transverse movement driving mechanism (33) is as follows: the end of the driving screw (3301) with a smaller diameter is first installed with a No. 1 thrust ball bearing (3305), and then passes through the through hole of the main transverse beam (27). The No. 1 thrust ball bearing (3305) is embedded in the installation seat to play a role of rotation support. The No. 2 thrust ball bearing (3306) and the retaining ring body (3304) are installed on the penetrated part. The through hole diameter of the main transverse beam (27) is smaller than the diameter of the No. 1 thrust ball bearing (3305) and the No. 2 thrust ball bearing (3306). The No. 1 thrust ball bearing (3305) and the No. 2 thrust ball bearing (3306) are blocked by the main transverse beam (27). The end of the driving screw (3301) with a smaller diameter is machined with a small section of fine thread. The No. 2 thrust ball bearing (3306) and the retaining ring body are fixed by a small round nut (3307). (3304) fits tightly against the main transverse beam (27), and the handle (3308) is installed at the end to facilitate the rotation of the driving screw (3301). The nut (3302) is inverted on the translation frame (15), and the end of the driving screw (3301) with a larger diameter is coarsely threaded and used in conjunction with the nut (3302); the handle (3308) is turned to drive the screw (3301) to drive the nut (3302), and the translation frame (15) can move laterally under the guidance of the transverse moving slider (30) and the transverse moving rail (7). Two limit blocks (31) are installed on each transverse moving rail (7), and the two limit blocks (31) are distributed on both sides of the translation frame (15). When the translation frame (15) moves laterally to a predetermined position, the transverse position of the translation frame (15) is locked by using the fastener and the limit block (31).

10. A method for using the forced restraint device for a towing tank PIV test model as claimed in claim 1, characterized in that: The process includes: Draw a waterline for the test ship model (3) in a free-navigation state on the water platform, and draw a reference waterline about 1 cm below the waterline; The forced restraint device is located on the trailer test platform (1), and the slider rail (5) and the gear rail (6) cooperate with the slide rail bar and the gear bar on the test platform (1) to play a guiding role. By rotating the cylindrical gear (3406), the forced restraint device can slide along the slide rail bar or the gear rail bar under the interaction of the gear and the gear bar. A locking assembly is provided to keep the positions of the forced restraint device and the slide rail bar or the gear rail bar unchanged; The lifting rod (23) is fixed to the ship model via the model connection seat (11), and the model connection seat (11) releases the longitudinal tilt constraint, so as to adapt to different longitudinal tilt angle requirements of the ship model in a free state; The lifting rod (23) is driven to move vertically by the motor (10) and the worm gear mechanism (13); A weight is placed inside the test ship model (3) until the reference waterline is flush with the water surface, and the heights of the two forced restraint device lifting rods (23) are adjusted to press the test ship model (3) downward so that the free navigation state waterline is flush with the water surface. Then, the model connecting seat (11) and the test ship model (3) are connected, and the heave and pitch attitude of the test ship model (3) can be locked.

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