An internal solitary wave force measuring device, system and method

Abstract

The application relates to the technical field of internal solitary wave experiment, and particularly provides an internal solitary wave acting force measuring device, system and method, which are used for measuring the internal solitary wave acting force on an underwater target arranged in an experimental pool, and comprise a first measuring part, a second measuring part, an acting force transmission part for rigidly connecting the first measuring part and the second measuring part, and a supporting part for positioning the measuring parts; the first measuring part comprises a first upper connecting rod, a first load cell and a first lower connecting rod which are sequentially connected along a Z-axis direction; the second measuring part comprises a second upper connecting rod, a second load cell and a second lower connecting rod which are sequentially connected along a theta angle direction; and the theta angle is arranged so that a torque M2' on the second load cell is smaller than a torque limit of the second load cell. The measuring device and system provided by the application can accurately measure the internal solitary wave acting force on the underwater target, and have low cost and simple operation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of internal solitary wave experiment, and particularly relates to an internal solitary wave acting force measuring device, system and method. BACKGROUND

[0002] Internal wave is a disturbance existing in stratified fluid in the ocean. Generally, the internal solitary wave with a wavelength of 1-2 times the length of a submerged body is referred to as an internal solitary wave. As a special nonlinear internal wave, the internal solitary wave will cause the submerged body to make large amplitude up and down fluctuations with the internal solitary wave in the propagation process, which will greatly affect the stability and controllability of the submerged body. Therefore, it is of great value to study the influence of the internal solitary wave on the hydrodynamic performance of the submerged body.

[0003] Internal solitary wave pool experiment is an important means to study the influence of the internal solitary wave on the hydrodynamic performance of the submerged body. At present, quite a few schemes about the internal solitary wave pool experiment have been disclosed. For example, patent 201810114516.7 discloses an experimental system for interaction between internal wave and submerged body, which measures the forces in three directions by using three pressure sensors arranged at the head, middle and side of the submerged body model. However, the measurement position of the above-mentioned mode is the surface of the submerged body model, and the force condition at the center of mass cannot be directly obtained. In addition, due to the characteristics of the internal solitary wave, the horizontal and vertical forces may differ by an order of magnitude. In order to ensure the experimental accuracy, sensors with different ranges and accuracies are required, which increases the price and use cost of the experimental device. For another example, patent 202211064910.7 proposes an embedded force measuring method for the interaction between underwater structure and internal solitary wave, which embeds a force measuring sensor into the submerged body model to measure the three-dimensional force data of the structure model when the internal solitary wave passes. However, a multi-component force sensor that meets the requirements of one-tenth of the horizontal and vertical force accuracy and range needs to be customized separately, and its price is much higher than that of a single-component force sensor. In addition, the sensor is built-in in the submerged body model in the scheme, and the fluid environment of the experiment usually contains oil and water, which greatly increases the complexity of the installation and sealing of the sensor, and undoubtedly increases the probability of damage to the sensor. Therefore, the applicant has developed a multi-link structure, which can decompose the force of the submerged body into horizontal and vertical components by using the multi-link structure. Two single-component force sensors can be used to measure the two components, and the lever principle is used to amplify the horizontal force and transmit it to the measurement part, so that the size of the internal solitary wave acting force in each direction component is in the same order of magnitude. However, in actual operation, the scheme causes new error problems due to too many connecting points caused by too many rods. In addition, the friction between the parts in the scheme also affects the measurement results of the small force.

[0004] Therefore, it is necessary to optimize the measurement system for internal solitary waves in a targeted manner to solve the problems existing in the various water tank experimental schemes. Summary of the Invention

[0005] The purpose of this application is to provide an internal solitary wave force measurement device, system and method to solve the problem of how to achieve accurate, low-cost and convenient measurement of internal solitary wave force in a water tank experimental environment.

[0006] The embodiments of this application can be implemented through the following technical solutions:

[0007] An internal solitary wave force measuring device is used to measure the internal solitary wave force on an underwater target deployed in an experimental water tank. It includes a first measuring unit, a second measuring unit, a force transmission unit for rigidly connecting the first and second measuring units, and a support unit for positioning each measuring unit. The first measuring unit includes a first upper connecting rod, a first force gauge, and a first lower connecting rod connected sequentially along the Z-axis. In use, the first lower connecting rod is connected to the center of mass of the underwater target. The first force gauge measures the force along the Z-axis to obtain the force of the internal solitary wave on the underwater target in the Z-axis direction. The second measuring unit includes a second upper connecting rod, a second force gauge, and a second lower connecting rod connected sequentially along an θ-angle direction. The θ-angle direction is a direction in the XZ plane that deviates from the Z-axis by an angle θ. The second force gauge measures the force in the θ-angle direction to obtain the force of the internal solitary wave on the underwater target in the X-axis direction. The θ-angle is set such that the torque M'2 on the second force gauge is less than the torque limit of the second force gauge.

[0008] Furthermore, the force transmission part includes a first connecting part, a corner part, and a second connecting part. The first connecting part and the second connecting part are respectively provided with a first fixing groove and a second fixing groove that cooperate with the first upper connecting rod and the second lower connecting rod. The angle of the corner part is 180-θ°.

[0009] Furthermore, one end of the second lower connecting rod is fixed in the second fixing groove, and the other end is fixedly connected to the inside of the second force gauge. The length of the second lower connecting rod is set to allow the second force gauge to contact the second connecting part.

[0010] Furthermore, the second lower link and the first upper link are hinged together by a force transmission part.

[0011] Furthermore, the force transmission part includes through holes respectively disposed at the ends of the first upper connecting rod and the second lower connecting rod, and bolts that are connected thereto.

[0012] Furthermore, it also includes an adjusting limiting mechanism, one end of which is slidably connected relative to the support part along the X-axis direction, and the other end is detachably connected to the second upper connecting rod.

[0013] Furthermore, the adjustment limiting mechanism includes a first limiting block and a second limiting block, wherein the first limiting block is slidably connected to the support along the X-axis, and the second limiting block is rotatably connected to one side of the first limiting block along the Y-axis, with its rotation direction parallel to the XZ plane. The second limiting block is provided with a through hole matching the second upper connecting rod and a fastening structure.

[0014] Furthermore, the first lower link and / or the second upper link are length-adjustable links.

[0015] Furthermore, the support unit includes a longitudinal support unit, a transverse support unit, a vertical support unit that cooperate with each other, and an upper top plate disposed above the transverse support unit. In use, the support unit can be slidably disposed above the experimental water tank.

[0016] Furthermore, in use, the longitudinal support unit of the support part can slide relative to the experimental water tank along the X-axis direction; the upper top plate is movably connected to other support units, allowing it to slide relative to the experimental water tank along the Y-axis direction.

[0017] Furthermore, the support also includes auxiliary positioning structures for placement at the front and rear of the underwater target. The auxiliary positioning structures include at least two auxiliary links, each of which is fixedly connected to a collar. The two auxiliary links pass through the transverse support and the top plate that they cooperate with, and can be adjusted in height in the vertical direction and limited by a joint.

[0018] An internal solitary wave force measurement system includes an experimental water tank, a wave-generating mechanism, a wave-dissipating mechanism, and an underwater target. The experimental water tank is filled with at least two liquids of different densities. The wave-generating mechanism is used to generate internal solitary waves that propagate in the two liquids of different densities. The wave-dissipating mechanism is used to eliminate the internal solitary waves. Further, it also includes an internal solitary wave force measurement device as described in any one of the above-mentioned methods, used to measure the internal solitary wave force acting on the underwater target.

[0019] A method for measuring the force of an internal solitary wave, using the aforementioned internal solitary wave force measurement system, includes the following steps:

[0020] S1 assembles and positions the various devices so that the first connecting rod 12 is connected to the center of mass of the underwater target;

[0021] S2 generates an internal solitary wave in the experimental water tank;

[0022] S3 measures the force in the vertical direction and the force in the θ angle direction acting on the underwater target through the first measuring unit and the second measuring unit, respectively;

[0023] S4 calculates the horizontal force acting on the underwater target based on the measurement results of the first and second measuring units in S3 through force balance decomposition.

[0024] The embodiments of this application provide an internal solitary wave force measurement device, system, and method that have at least the following beneficial effects:

[0025] This application can measure the vertical force of an internal solitary wave through a first measuring unit. By setting the second measuring unit to deflect the first measuring unit by an angle θ, the force in this direction can be measured. The horizontal force of the internal solitary wave can be obtained through simple force decomposition calculation. By setting the range of the angle θ, the influence of torque on the measurement accuracy is avoided. This solution is lower in cost and simpler to measure than existing solutions, and can ensure the accuracy of the measurement. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a sensor setup for testing the force of internal solitary waves acting on an underwater target.

[0027] Figure 2 This is a schematic diagram of the layout of the internal solitary wave force measurement system provided according to an embodiment of this application;

[0028] Figure 3 This is a schematic diagram of the layout of the internal solitary wave force measuring device according to the embodiments of this application;

[0029] Figure 4 This is a side view of the internal solitary wave force measuring device provided according to an embodiment of this application;

[0030] Figure 5 This is a schematic diagram illustrating the force analysis principle according to an embodiment of this application;

[0031] Figure 6 This is a cross-sectional view of the force transmission section according to an embodiment of this application;

[0032] Figure 7 This is a cross-sectional view of the force transmission section according to an embodiment of this application;

[0033] Figure 8 This is a schematic diagram of an adjusting limit mechanism according to an embodiment of this application.

[0034] Numbers in the diagram

[0035] First measuring unit 1, first force gauge 11, first lower connecting rod 12, first upper connecting rod 13

[0036] Second measuring unit 2, second force gauge 21, second lower connecting rod 22, second upper connecting rod 23

[0037] Force transmission part 3, first connecting part 31, corner part 32, second connecting part 33

[0038] Support unit 4, longitudinal support unit 41, transverse support unit 42, vertical support unit 43, top plate 44, auxiliary connecting rod 461, collar 462

[0039] Adjustable limiting mechanism 5, first limiting block 51, second limiting block 52, through hole 521, fastening structure 522.

[0040] Experimental water tank 7, water tank wall 71, horizontal support for the water tank 72, vertical support for the water tank 73.

[0041] Measuring device 8,

[0042] Underwater target 9, center of mass 91, measurement point 901, measurement point 902, measurement point 903. Detailed Implementation

[0043] The present application will now be further described based on preferred embodiments and with reference to the accompanying drawings.

[0044] Furthermore, for ease of understanding, various components on the drawings have been enlarged or reduced, but this is not intended to limit the scope of protection of this application.

[0045] Singular forms of words also include plural meanings, and vice versa.

[0046] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, in the description of this application, in order to distinguish different units, the terms "first," "second," etc. are used in this specification, but these are not limited by the manufacturing order, nor should they be construed as indicating or implying relative importance. Their names may differ in the detailed description and claims of this application.

[0047] The vocabulary used in this specification is for illustrative purposes and is not intended to limit the scope of this application. It should also be noted that, unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection via an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of these terms in this application.

[0048] In the embodiments of this application, the X-axis direction represents the horizontal propagation direction of the internal solitary wave, the Z-axis direction is the vertical direction, and the Y-axis direction is another horizontal direction perpendicular to the X-axis. The X, Y, and Z axes are mutually orthogonal to each other.

[0049] To explain the technical solution of this application in detail, we will first introduce the method of measuring the force of internal solitary waves on underwater targets in existing water tank experiments.

[0050] Figure 1 This paper illustrates a scheme for measuring the internal solitary wave force by deploying multiple force sensors on the surface of an underwater target 9. The underwater target 9 can be a scaled-down model of a real underwater submersible, such as... Figure 1 As shown, pressure sensors are installed at measurement point 901 directly in front of underwater target 9, measurement point 902 to the side, and measurement point 903 directly above underwater target 9 to obtain the components of the internal solitary wave force acting on underwater target 9 in various directions. However, this measurement scheme has the following problems that need to be overcome in the actual force measurement process:

[0051] 1) Since the sensors are deployed at various points on the outer surface of the underwater target 9, the measured results are not the force exerted on the center of mass 91 (obviously, it is impossible to place more than one sensor at the center of mass 91). At the same time, since the shape of the underwater target 9 is irregular, it is necessary to perform cumbersome calibration or add additional attitude measurement devices such as gyroscopes to ensure that the force directions of each sensor are orthogonal to each other, which undoubtedly increases the complexity of experimental operation and data processing.

[0052] 2) Due to the characteristics of internal solitary waves, the vertical force at their point of action often exceeds the horizontal force along the propagation direction by an order of magnitude. Simultaneously, the horizontal force along the propagation direction is significantly greater than the force in another horizontal direction perpendicular to it. Figure 1 With the setup shown, the force components of the internal solitary wave measured at the three measurement points 901, 902, and 903 exhibit the following relationship:

[0053] F 903 >>F 901 >>F 902 ;

[0054] Obviously, if a single-component force sensor of the same specification is selected, and it meets the resolution requirements to be able to handle smaller forces such as F... 901 or F 902 When measuring F precisely, then 903 It may have exceeded its measurement range; conversely, if the safety of the measurement range is prioritized, it may not be possible to accurately measure the minute components of the force.

[0055] 3) This scheme places multiple sensors directly in liquids such as oil and water, which not only greatly increases the probability of sensor damage, but also makes it difficult to flexibly adjust the depth of underwater targets.

[0056] Apart from Figure 1 In addition to the scheme shown, there is also a technical scheme that directly places the multi-component force sensor inside the underwater target 9, such as at the center of mass 91, so as to directly collect the three orthogonal components of the internal solitary wave force at that location. Generally, this scheme requires the use of a high-precision measuring instrument: a six-component force sensor, which can simultaneously measure the force and torque of an object on three mutually perpendicular principal axes, hence the name six-component force sensor.

[0057] The measurement principle of a six-component force sensor is based on the bridge balance of strain gauges. The magnitude of force and torque is calculated by measuring the resistance change of the strain gauges. In a six-component force sensor, three mutually perpendicular strain gauges are usually used as the bridge arms of the bridge. Two strain gauges are used to measure the force and torque in the X and Y axes, and the third strain gauge is used to measure the force and torque in the Z axis. When an object is placed on the measurement platform of the six-component force sensor, the strain gauges will deform due to the force and torque, causing their resistance to change. By measuring the change in resistance, the magnitude of the force and torque on the object can be calculated.

[0058] There are many factors that affect the accuracy of a six-component force sensor, the most important of which is interdimensional coupling. In physics, this refers to the phenomenon where two or more systems or two forms of motion influence each other and even combine through interaction. In a six-component force sensor, the input signal in each of the six channels will affect the output signal of the other channels. Therefore, it is almost impossible to have one input control only one output without affecting the other channels. Thus, the raw signals collected by the multi-component force sensor must undergo decoupling to eliminate the coupling effect between signals in different directions.

[0059] Generally, eliminating or suppressing coupling can be done in two ways. The first is to do the work before manufacturing the sensor, which is generally called structural decoupling. This means eliminating or suppressing coupling from the design of the sensor. This method involves the manufacturing process of the sensor, which is often difficult and may increase costs. The second method is to use a systematic mathematical model to perform matrix operations for decoupling.

[0060] However, as analyzed above, due to the order-of-magnitude difference in the magnitudes of the three orthogonal components of the internal solitary wave, multi-force sensors need to achieve high-precision measurements across a range spanning orders of magnitude. Therefore, if structural decoupling is adopted, multi-force sensors need to be customized separately according to the range and accuracy specifications of each direction. If mathematical matrix operation decoupling is adopted, the order-of-magnitude difference in the signals in each direction will have a great impact on the accuracy of matrix operation, and may even lead to the inability to obtain a stable solution.

[0061] Furthermore, since the expensive multi-force sensor needs to be placed below the surface of a mixture of liquids such as water and oil, higher requirements are obviously placed on the watertight structure of the underwater target 9 in order to reduce the probability of damage to the multi-force sensor.

[0062] It is evident that how to achieve accurate, low-cost, and convenient measurement of the force of internal solitary waves in a water tank experimental environment is an urgent problem to be solved. To this end, this application provides an internal solitary wave force measuring device and a measurement system using the device through embodiments.

[0063] Figure 2 A schematic diagram of an internal solitary wave force measurement system according to some embodiments of the present application is shown. The system includes an experimental water tank 7 filled with at least two liquids of different densities, a wave-generating mechanism and a wave-dissipating mechanism (not shown) for generating and eliminating internal solitary waves in the experimental water tank, and an underwater target 9 deployed in the experimental water tank. In addition, it also includes an internal solitary wave force measurement device 8 according to some embodiments of the present application.

[0064] The experimental water tank 7 can be constructed using methods known to those skilled in the art. For example, a frame structure of the water tank can be constructed from multiple horizontal supports 72 and vertical supports 73, with various watertight materials used as the tank walls 71 and bottom within the frame structure, thus obtaining the experimental water tank 7. Figure 2The diagram shows a long, narrow experimental water tank 7 extending along the X-axis. One end of the tank is equipped with a wave-generating mechanism, which generates an internal isolated wave that propagates unidirectionally along the X-axis at the interface between two liquids. When the internal isolated wave passes the underwater target 9, the force exerted by the internal isolated wave on the underwater target 9, which is below the liquid level in the experimental water tank 7, can be measured by a measuring device 8. The other end of the experimental water tank 7 is equipped with a wave-damping mechanism to prevent the internal isolated wave from propagating in the reverse direction within the experimental water tank.

[0065] Figure 3 and Figure 4 The specific structure of an internal solitary wave force measuring device 8 provided according to some embodiments of this application is shown. The measuring device 8 includes a first measuring part 1, a second measuring part 2, a force transmission part 3, and a support part 4.

[0066] The first measuring unit 1 includes a first upper connecting rod 13, a first force gauge 11 and a first lower connecting rod 12 connected in sequence along the Z-axis. In use, the first lower connecting rod 12 is connected to the center of mass 91 of the underwater target 9. The first force gauge 11 is used to measure the force along the Z-axis to obtain the force of the internal solitary wave on the underwater target in the Z-axis direction.

[0067] The second measuring unit 2 includes a second upper connecting rod 23, a second force gauge 21, and a second lower connecting rod 22 connected sequentially along the θ angle direction. The θ angle direction is the direction in the XZ plane that deviates from the Z-axis by an angle of θ. The second force gauge 21 is used to measure the force in the θ angle direction to obtain the force exerted by the internal solitary wave on the underwater target in the X-axis direction.

[0068] Specifically, both the first force gauge 11 and the second force gauge 21 are unidirectional force gauges, and in some specific embodiments, they are both S-type sensors.

[0069] The force transmission unit 3 is connected to the ends of the first upper connecting rod 13 and the second lower connecting rod 22 respectively, so as to rigidly connect the first measuring unit 1 and the second measuring unit 2, so that all the force at the center of mass 91 is transmitted to the second force gauge 21 for collection.

[0070] The support part 4 is located above the experimental water tank 7 and is used to position and support the measuring device 8. Specifically, the support part 4 includes a longitudinal support unit 41 composed of multiple longitudinal supports, a transverse support unit 42 composed of multiple transverse supports, a vertical support unit 43 composed of multiple vertical supports, and an upper top plate 44 located above the transverse support unit 42. The units cooperate with each other and are fixedly connected to the top of the experimental water tank 7.

[0071] The following combination Figure 5 Further explanation of the principles of this application:

[0072] When the internal solitary wave propagates along the X-axis to the underwater target 9, the underwater target 9 will simultaneously experience a vertical force F along the Z-axis (vertical direction). z And the horizontal force F along the X-axis (direction of propagation of the internal solitary wave). x The force exerted by the aforementioned internal solitary wave on the underwater target 9 can be represented by the force acting on the underwater target 9 at its center of mass 91.

[0073] Since one end of the first lower connecting rod 12 of the first measuring unit 1 is fixedly connected to the center of mass 91 and the other end is fixedly connected to the first force gauge 11, the force at the center of mass 91 is transmitted to the first force gauge 11 for collection through the first lower connecting rod 12. At this time, the force at the first force gauge 11 can be decomposed into a first vertical force F' along the Z-axis direction. z1 and the first horizontal force F' along the X-axis x1 Since the first force gauge 11 is a unidirectional force gauge, it is used to measure the first vertical force F'. z1 When the first force gauge 11 is subjected to a force other than the measuring direction (i.e., the Z-axis direction) (i.e., F') x1 In the ideal state, where the measurement accuracy is not affected, the vertical force F acting on the underwater target 9 along the Z-axis can be obtained by the following formula (1). z :

[0074] F z =F' z1 (1);

[0075] Since the second measuring unit 2 is rigidly connected to the first measuring unit 1 through the force transmission unit 3, the force acting on the center of mass 91 is also fully transmitted to the second force gauge 21 for collection. This application sets the second measuring unit 2 in the θ-angle direction, that is, in the XZ plane, it deviates from the Z-axis in the θ-angle direction. Figure 5 As shown, the force on the second force gauge 21 at this time can be decomposed into a second vertical force F' along the θ angle direction. z2 and the second horizontal force F' perpendicular to the θ angle direction x2 In addition, it is also subjected to torque M'1. The second force gauge 21 is used to measure the force along the θ angle direction. According to the force balance decomposition, the following relationship (2) can be obtained:

[0076] F z ×cosθ+F x ×sinθ=F' z2 (2);

[0077] Similarly, under ideal conditions, the reading measured by the second force gauge 21 is F'. z2The vertical force F acting on the underwater target 9 along the X-axis can be calculated using the following formula (3) by formulas (1) and (2) above. x :

[0078] F x =(F' z2 -F' z1 cosθ) / sinθ (3);

[0079] However, in reality, when a unidirectional force gauge is subjected to forces and torques in other directions, especially torques, while measuring forces in the measurement direction, it will have a certain impact on its safety and measurement accuracy. Therefore, in order to ensure the normal and safe operation of the force gauge and the accuracy of the measurement, it is necessary to operate within the torque limit of the force gauge. For example, taking the S-type sensor as an example, when its measurement range is 10N, the torque it receives cannot exceed 0.25Nm.

[0080] As described above, for the first measuring unit 1, the torque M'1 on the first force gauge 11 can be calculated according to the following formula (4):

[0081] M'1=F' x1 ×L1=F x ×L1 (4);

[0082] In the formula, L1 is the first lever arm, which is the distance from the first force gauge 11 to the center of mass 91 of the underwater target. As described in the background art, the horizontal force generated by the internal solitary wave is often small, differing from the vertical force by an order of magnitude. Therefore, the above F' x1 Much smaller than F' z1 When F' z1 Within the range of the first force gauge 11, the torque M'1 is always within the torque limit of the first force gauge 11, and therefore will not affect its safety or measurement accuracy. Thus, the force of the internal solitary wave in the Z-axis direction acting on the underwater target 9 can be directly obtained from the measurement reading of the first force gauge 11 with relatively accurate accuracy. Clearly, the torque M'1, besides being related to F' x1 In addition to the related factors, it is also related to the first lever arm L1. The closer the distance, the smaller the torque M'1 on the first force gauge 11, and the more accurate the measurement result. However, if the first force gauge 11 is assembled at the center of mass of the underwater target 9, the first force gauge 11 needs to be watertight. Obviously, this places higher demands on the watertight structure of the underwater target 9. Therefore, in some preferred embodiments, the first force gauge 11 is set close to the center of mass of the underwater target 9 and above the liquid surface of the experimental water tank.

[0083] Similarly, for the second measuring unit 2, the torque M'2 it experiences can be calculated using the following formula (5):

[0084] M'2=(F z ×sinθ±F x ×cosθ)×L2 (5);

[0085] In the formula, L2 is the second lever arm, which is the distance from the second force gauge 21 to the inflection point A where the first measuring part 1 and the second measuring part 2 intersect. By analyzing equation (5), it can be seen that the smaller the angle θ and the value of L2, the smaller the value of M'2, and the smaller the impact of torque M'2 on the accuracy of the second force gauge 21. However, since the measuring device itself also has other unavoidable systematic errors, as described in the background art description F x The systematic error is usually small, therefore the systematic error has little effect on F. x The measurement of θ has a significant impact, and the smaller the θ value, the greater the impact of F. x The proportion F in the second force gauge x The smaller sinθ is, the greater the impact of systematic errors. Therefore, it is necessary to select an appropriate θ angle based on actual needs. Preferably, the θ angle should be increased as much as possible while ensuring that M'2 is less than its torque limit, in order to reduce the impact of systematic errors.

[0086] Therefore, this application further optimizes the structure and position of the second measuring unit 2. On the one hand, it can make the torque M'2 in the non-measuring direction of the second force gauge 21 less than its torque limit, so as to keep the measurement results accurate. On the other hand, it can also minimize the impact of system errors.

[0087] In some preferred embodiments, the maximum horizontal force F of the internal isolated wave that the experimental pool 7 can provide can be determined empirically. x,max Maximum vertical force F z,max According to the maximum vertical force F z,max The range of θ is determined by the torque limit of the pre-selected force gauge and the value of the second lever arm L2. For example, when the maximum horizontal force F... x,max and the maximum vertical force F z,max With torques of 0.6N and 10N respectively, the torque limit of the selected force gauge is 0.25Nm. When the value of the second lever arm L2 is 0.1m, the maximum value of the angle θ can be calculated to be approximately 9.8°. When the angle θ is less than this value, the torque M'2 generated by the second force gauge does not exceed the torque limit, and the measurement results are accurate.

[0088] Specifically, the setting of the θ angle is achieved through the specific structure of the force transmission unit 3. Figure 6The specific structure of the force transmission part 3 in some embodiments of this application is shown. It includes an integral connector composed of a first connecting part 31, a corner part 32, and a second connecting part 33. The first connecting part 31 and the second connecting part 33 are respectively provided with a first fixing groove and a second fixing groove that cooperate with the first upper connecting rod 13 and the second lower connecting rod 22. The ends of the first upper connecting rod 13 and the second lower connecting rod 22 are respectively inserted into the fixing grooves at both ends to achieve a fixed connection. The angle of the corner part 32 is 180-θ° to achieve the second lower connecting rod 22 being connected relative to the first upper connecting rod 13 by deflecting at an angle θ. Specifically, the fixing groove and the rod can be connected by threaded connection or interference fit. In use, the angle θ can be changed by replacing the force transmission part 3 with different angles.

[0089] In addition to optimizing the θ angle setting, the second lever arm L2 can also be optimized. In some preferred embodiments, such as... Figure 7 As shown, when the force transmission part 3 is an integral connector, one end of the second lower connecting rod 22 is fixed in the second fixing groove, and the other end is fixedly connected to the inside of the second force gauge 21. The length of the second lower connecting rod 22 is set so that the second force gauge 21 can contact the second connecting part 33. That is, by reducing the second lever arm L2, the influence of the second torque M'2 on the measurement result of the second force gauge 21 is further reduced, and the measurement accuracy of the second force gauge 21 is improved. In addition, reducing the second lever arm L2 can also increase the angle θ while meeting the measurement accuracy requirements of the second force gauge 21, and reduce the influence of system error.

[0090] In addition, in order to measure the force of internal isolated waves at different locations in the experimental water tank 7 and to better study the characteristics of internal isolated waves, the applicant has made further improvements to the above-mentioned measuring device 8.

[0091] In some preferred embodiments, the support 4 is movably connected to the experimental water tank 7, allowing the longitudinal support unit to slide along the X-axis direction along the experimental water tank 7; in some preferred embodiments, the upper top plate 44 is movably connected to other support units, allowing it to slide relative to the experimental water tank 7 along the Y-axis direction; so as to enable the measurement of forces at different positions on the XY plane.

[0092] In some preferred embodiments, the first lower connecting rod 12 is a length-adjustable connecting rod, and the measurement depth of the underwater target 9 can be quickly changed by adjusting the length of the first lower connecting rod 12. In some specific embodiments, the length-adjustable connecting rod can be composed of two interlocking rods, that is, one rod is set as a hollow cylindrical tube so that it can be sleeved on the outside of the other, and the two have a stud structure and a screw hole structure that cooperate with each other, and the degree of extension and retraction between the two can be adjusted by rotation; in some other embodiments, the length-adjustable connecting rod is composed of two interlocking rods, one rod is provided with multiple through holes arranged axially at intervals, and the other rod is provided with a ball that can be pressed and bounced up after the pressing is released. When the two rods move axially relative to each other, the ball bounces up after entering a certain through hole, limiting the position of the two rods, thereby realizing the length adjustment.

[0093] In some preferred embodiments, the force transmission part 3 may also be a hinged structure, so that the appropriate θ angle can be adjusted according to the rapid changes in experimental conditions such as the amplitude of the internal solitary wave and the measurement position during the experiment, so as to achieve more accurate measurement; specifically, the hinged structure includes through holes respectively provided at the ends of the first upper connecting rod 13 and the second lower connecting rod 22, and bolts that cooperate with them.

[0094] In some preferred embodiments, an adjusting limiting mechanism 5 is further included, which is detachably connected to the second upper connecting rod 23 for limiting its position. The second upper connecting rod 23 is provided with scale lines. In use, different measurement positions are achieved by adjusting the limiting positions of the second upper connecting rod 23 and the adjusting limiting mechanism 5. Figure 8 As shown, in some embodiments of this application, the adjusting limiting mechanism 5 includes a first limiting block 51 and a second limiting block 52, which are rotatably connected to each other. The first limiting block 51 is fixedly connected to the support part 4, and the second limiting block 52 is rotatably connected to one side of the first limiting block 51 along the Y-axis, with its rotation direction parallel to the XZ plane. Further, the second limiting block 52 is provided with a through hole 521 that matches the second upper connecting rod 23, and a fastening structure 522. Specifically, the fastening structure 522 is a set screw. The positioning of the second measuring part 2 and its rotation in the XZ plane can be realized by adjusting the limiting mechanism 5.

[0095] Furthermore, the adjusting and limiting mechanism 5 is slidably connected to the support unit of the support part 4. Specifically, the slidable connection can be achieved by setting a sliding groove slider structure. Preferably, the sliding direction is parallel to the X-axis direction.

[0096] Furthermore, the second upper connecting rod 23 is a length-adjustable connecting rod, which works in conjunction with the hinge structure of the force transmission part 3 and the adjustment and limiting mechanism 5 to achieve rapid adjustment of different θ angles and different positions. The specific structure of the length-adjustable connecting rod is similar to that of the first lower connecting rod 12, and will not be described in detail here.

[0097] In some preferred embodiments, the support 4 further includes auxiliary positioning structures respectively disposed at the front and rear of the underwater target 9. Specifically, the auxiliary positioning structure includes at least two auxiliary connecting rods 461, each of which is fixedly connected to a collar 462. The two collars 462 are respectively fitted onto the front and rear of the underwater target 9. The two auxiliary connecting rods 461 pass through the transverse support and the upper top plate 44 that cooperate with them, and can be adjusted in height in the vertical direction and limited by a joint. Using the auxiliary positioning structure, when adjusting the length of the first lower connecting rod 12, the underwater target 9 can be assisted in being adjusted to the expected depth and maintaining its orientation.

[0098] In some preferred embodiments, a counterweight is also provided inside the underwater target 9. The appropriate counterweight can be set according to the weight and buoyancy of the underwater target 9 so that the underwater target 9 does not exert any force on each force gauge when the internal solitary wave does not arrive.

[0099] This application also provides a method for measuring the force of an internal solitary wave, which is operated using the aforementioned internal solitary wave force measurement system. In some specific embodiments, it includes the following steps:

[0100] S1 assembles and positions the various devices so that the first lower connecting rod 12 is connected to the center of mass 91 of the underwater target 9;

[0101] S2 generates an internal solitary wave within the experimental water tank 7;

[0102] S3 measures the vertical force and the force in the θ angle direction acting on the underwater target 9 through the first measuring unit 1 and the second measuring unit 2, respectively.

[0103] S4 calculates the force acting on the underwater target 9 in the horizontal direction based on the measurement results of the first measuring unit 1 and the second measuring unit 2 in S3 through force balance decomposition.

[0104] Specifically, the force measured by the first measuring unit 1 in S3 is F'. z1 The force F acting on the underwater target 9 in the vertical direction can be obtained through the following formula (1). z :

[0105] F z =F' z1 (1);

[0106] Specifically, the horizontal force F acting on the underwater target 9 in S4 x Based on the measurement result F' of the first measuring unit 1 z1 The measurement result F' of the second measuring unit 2 z2 The following equation (3) is used to obtain:

[0107] F x =(F' z2 -F' z1 cosθ) / sinθ (3);

[0108] The specific embodiments of this application have been described in detail above. For those skilled in the art, several improvements and modifications can be made to this application without departing from the principle of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A device for measuring the force of an internal solitary wave, used to measure the force of an internal solitary wave acting on an underwater target deployed in an experimental water tank, characterized in that, It includes a first measuring part (1), a second measuring part (2), a force transmission part (3) for rigidly connecting the first measuring part (1) and the second measuring part (2), and a support part (4) for positioning each measuring part; The first measuring unit (1) includes a first upper connecting rod (13), a first force gauge (11) and a first lower connecting rod (12) connected sequentially along the Z-axis. In use, the first lower connecting rod (12) is connected to the center of mass (91) of the underwater target (9). The first force gauge (11) is used to measure the force along the Z-axis to obtain the force exerted by the internal solitary wave on the underwater target in the Z-axis direction. The second measuring unit (2) includes a second upper connecting rod (23), a second force gauge (21), and a second lower connecting rod (22) connected sequentially along the θ angle direction. The θ angle direction is the direction in the XZ plane that deviates from the Z-axis by an angle of θ. The second force gauge (21) is used to measure the force in the θ angle direction to obtain the force exerted by the internal solitary wave on the underwater target in the X-axis direction. The angle θ is set such that the torque M on the second force gauge (21) is... ' 2 is less than the torque limit of the second force gauge (21).

2. The internal solitary wave force measuring device according to claim 1, characterized in that, The force transmission part (3) includes a first connecting part (31), a corner part (32), and a second connecting part (33). The first connecting part (31) and the second connecting part (33) are respectively provided with a first fixing groove and a second fixing groove that cooperate with the first upper connecting rod (13) and the second lower connecting rod (22). The angle of the corner part (32) is 180-θ°.

3. The internal solitary wave force measuring device according to claim 2, characterized in that, One end of the second lower connecting rod (22) is fixed in the second fixing groove, and the other end is fixedly connected to the inside of the second force gauge (21). The length of the second lower connecting rod (22) is set so that the second force gauge (21) can contact the second connecting part (33).

4. The internal solitary wave force measuring device according to claim 1, characterized in that, The second lower link (22) and the first upper link (13) are hinged through the force transmission part (3).

5. The internal solitary wave force measuring device according to claim 4, characterized in that, The force transmission part (3) includes through holes respectively provided at the ends of the first upper connecting rod (13) and the second lower connecting rod (22) and bolts that cooperate with them.

6. The internal solitary wave force measuring device according to claim 4, characterized in that, It also includes an adjustment limiting mechanism (5), one end of which is slidably connected to the support part (4) along the X-axis direction, and the other end is detachably connected to the second upper connecting rod (23).

7. The internal solitary wave force measuring device according to claim 6, characterized in that, The adjustment limiting mechanism (5) includes a first limiting block (51) and a second limiting block (52). The first limiting block (51) is slidably connected to the support (4) along the X-axis, and the second limiting block (52) is rotatably connected to one side of the first limiting block (51) along the Y-axis, with its rotation direction parallel to the XZ plane. The second limiting block (52) is provided with a through hole (521) matching the second upper connecting rod (23) and a fastening structure (522).

8. The internal solitary wave force measuring device according to claim 1, characterized in that, The first lower link (12) and / or the second upper link (23) are length-adjustable links.

9. The internal solitary wave force measuring device according to claim 1, characterized in that, The support part (4) includes a longitudinal support unit (41), a transverse support unit (42), a vertical support unit (43) that cooperate with each other, and an upper top plate (44) disposed above the transverse support unit. In use, the support part (4) can be slidably disposed above the experimental water tank.

10. The internal solitary wave force measuring device according to claim 9, characterized in that, In use, the longitudinal support unit (41) of the support part (4) can slide relative to the experimental water tank along the X-axis direction; the upper top plate (44) is movably connected to other support units, so that it can slide relative to the experimental water tank along the Y-axis direction.

11. The internal solitary wave force measuring device according to claim 10, characterized in that, The support (4) also includes an auxiliary positioning structure for setting on the front and rear of the underwater target (9). The auxiliary positioning structure includes at least two auxiliary links (461), each of which is fixedly connected to a collar (462). The two auxiliary links (461) pass through the transverse support and the top plate (44) that cooperate with them, and can be adjusted in the vertical direction and limited by a joint.

12. A system for measuring the force of an internal solitary wave, comprising an experimental water tank (7), a wave-generating mechanism, a wave-dissipating mechanism, and an underwater target (9), wherein the experimental water tank is filled with at least two liquids of different densities, the wave-generating mechanism is used to generate internal solitary waves propagating in the two liquids of different densities, and the wave-dissipating mechanism is used to eliminate the internal solitary waves, characterized in that, It also includes an internal solitary wave force measuring device as described in any one of claims 1 to 11, for measuring the internal solitary wave force acting on the underwater target.

13. A method for measuring the force of an internal solitary wave, using the internal solitary wave force measurement system of claim 12, characterized in that, Includes the following steps: S1 assembles and positions the various devices so that the first lower connecting rod (12) is connected to the center of mass (91) of the underwater target (9); S2 generates an internal solitary wave within the experimental water tank (7); S3 measures the vertical force and the force in the θ angle direction acting on the underwater target (9) through the first measuring unit (1) and the second measuring unit (2), respectively. S4 calculates the force acting on the underwater target (9) in the horizontal direction based on the measurement results of the first measuring unit (1) and the second measuring unit (2) in S3 through force balance decomposition.

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