Internal solitary wave acting force measuring device, system and method

Abstract

The invention relates to the technical field of internal solitary wave experiments, and particularly provides an internal solitary wave acting force measuring device, system and method which are used for measuring internal solitary wave acting force borne by an underwater target arranged in an experimental pool. The device comprises a first measuring part, a second measuring part, an acting force transmission part used for enabling the first measuring part and the second measuring part to be in rigid connection, and a supporting part used for positioning all the measuring parts. The first measuring part comprises a first upper connecting rod, a first dynamometer and a first lower connecting rod which are sequentially connected along the Z-axis direction; the second measuring part comprises a second upper connecting rod, a second dynamometer and a second lower connecting rod which are sequentially connected along the theta angle direction; the theta angle is set to enable the torque M2'borne by the second dynamometer to be smaller than the torque limit of the second dynamometer. The measuring device and system provided by the invention can accurately measure the internal solitary wave acting force borne by the underwater target, and are low in cost and simple and convenient to operate.

Description

Technical Field

[0001] The present application belongs to the technical field of internal solitary wave experiments, and specifically, relates to an internal solitary wave force measurement device, system and method. Background Art

[0002] Internal waves are disturbances existing in stratified fluids in the ocean. Generally, ocean internal waves with a wavelength of 1 to 2 times the length of a submerged body are called internal solitary waves. As a special type of nonlinear internal wave, internal solitary waves will cause the submerged body to fluctuate up and down with the internal solitary waves during its propagation, which will have a great impact on the stability and controllability of the submerged body. Therefore, it is of great value to study the influence of internal solitary waves on the hydrodynamic performance of underwater submerged bodies.

[0003] Internal solitary wave tank experiment is an important means to study the influence of internal solitary waves on the hydrodynamic performance of underwater submersibles. At present, quite a number of schemes for internal solitary wave tank experiments have been disclosed. For example, Patent 201810114516.7 discloses an experimental system for the interaction between internal waves and submersibles. Three pressure sensors arranged on the head, middle and side of the submersible model are used to measure the forces in three directions respectively. However, the measurement position of the above method is the surface of the submersible model, and the force condition at its center of mass cannot be directly obtained. At the same time, due to the characteristics of internal solitary waves, the horizontal and vertical forces may differ by an order of magnitude. In order to ensure the accuracy of the experiment, sensors with different ranges and accuracies need to be used to increase The price and usage cost of the experimental equipment have been improved; for example, patent 202211064910.7 proposes an embedded force measurement method for the interaction between underwater structures and internal solitary waves. The force sensor is embedded in the underwater structure model, and the three-dimensional force data of the structure model when the internal solitary wave passes is measured. However, multi-component force sensors that meet the requirements of one-tenth of the horizontal force and vertical force precision and range generally need to be customized separately, and their price is much higher than that of single-component force sensors. In addition, the sensor is built into the underwater submersible model in its solution. Since the fluid environment of the experiment usually contains oil and water, the complexity of operations such as sensor installation and sealing is greatly increased, which undoubtedly increases the probability of sensor damage. To this end, the applicant has developed a multi-link structure, through which the force on the underwater submersible can be decomposed into two components in the horizontal direction and the vertical direction. Two single-component force sensors can be used to measure the two components respectively, and the horizontal force can be amplified and transmitted to the measuring part by using the lever principle, so that the magnitudes of the components of the internal solitary wave force in each direction are within a consistent magnitude range. However, in actual operation, this scheme has new error problems due to too many connection points due to too many rods. In addition, the friction caused by excessive contact between the parts in this scheme will also affect the measurement results of smaller forces.

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

[0005] The purpose of the present 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 the internal solitary wave force in a water tank experimental environment.

[0006] The embodiments of the present 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 exerted on an underwater target arranged in an experimental water pool, comprising a first measuring part, a second measuring part, a force transmission part for rigidly connecting the first measuring part and the second measuring part, and a support part for positioning each measuring part; the first measuring part comprises a first upper connecting rod, a first dynamometer and a first lower connecting rod connected in sequence along the Z-axis direction, when in use, the first lower connecting rod is connected to the center of mass of the underwater target, the first dynamometer is used to measure the force along the Z-axis direction to obtain the force exerted by the internal solitary wave on the underwater target in the Z-axis direction; the second measuring part comprises a second upper connecting rod, a second dynamometer and a second lower connecting rod connected in sequence along the θ angle direction, the θ angle direction is a direction deviating from the Z axis by an angle θ in an XZ plane, the second dynamometer is used to measure the force exerted 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 θ angle is set so that the torque M2′ exerted on the second dynamometer is less than the torque limit of the second dynamometer.

[0008] Furthermore, the force transmission part includes a first connecting part, a corner part and a second connecting part, and 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, and 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 dynamometer. The length of the second lower connecting rod is set to enable the second dynamometer to contact the second connecting portion.

[0010] Furthermore, the second lower connecting rod and the first upper connecting rod are hinged via a force transmitting portion.

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

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

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

[0014] Furthermore, the first lower connecting rod and / or the second upper connecting rod are connecting rods with adjustable length.

[0015] Furthermore, the support portion includes a longitudinal support unit, a transverse support unit, a vertical support unit and an upper top plate arranged above the transverse support unit, which cooperate with each other. When in use, the support portion can be slidably arranged above the experimental water pool.

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

[0017] Furthermore, the support part also includes an auxiliary positioning structure for being arranged at the front and rear of the underwater target, the auxiliary positioning structure includes at least two auxiliary connecting rods, each of which is fixedly connected to the ring, and the two auxiliary connecting rods respectively penetrate the transverse bracket and the upper top plate that cooperate with them, and can adjust the height in the vertical direction and be limited by the joint.

[0018] A system for measuring the force of an internal solitary wave comprises an experimental water pool, a wave-making mechanism, a wave-breaking mechanism and an underwater target. The experimental water pool is filled with at least two liquids with different densities. The wave-making mechanism is used to generate an internal solitary wave that propagates in the two liquids with different densities. The wave-breaking mechanism is used to eliminate the internal solitary wave. Furthermore, the system further comprises an internal solitary wave force measuring device as described in any one of the above items, which is used to measure the internal solitary wave force exerted on the underwater target.

[0019] A method for measuring an internal solitary wave force is provided, which is operated using the internal solitary wave force measurement system, and comprises the following steps:

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

[0021] S2 creates an internal solitary wave in the experimental pool;

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

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

[0024] The internal solitary wave force measurement device, system and method provided by the embodiments of the present application have at least the following beneficial effects:

[0025] The present application can measure the vertical force of the internal solitary wave through the first measuring part, and measure the force in this direction by deflecting the second measuring part and the first measuring part by an angle θ. The horizontal force of the internal solitary wave can be obtained by simple force decomposition and calculation, and the influence of the torque on the measurement accuracy can be avoided by setting the range of the angle θ. This makes the present solution low in cost and simple in measurement compared to the existing solution, and can ensure the accuracy of the measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a sensor arrangement for testing the internal solitary wave force on an underwater target is provided;

[0027] Figure 2 A schematic diagram of the layout of an internal solitary wave force measurement system provided according to an embodiment of the present application;

[0028] Figure 3 A schematic diagram of the layout of an internal solitary wave force measurement device provided according to an embodiment of the present application;

[0029] Figure 4 It is a side view of an internal solitary wave force measurement device provided according to an embodiment of the present application;

[0030] Figure 5 It is a principle diagram of force analysis according to an embodiment of the present application;

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

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

[0033] Figure 8 It is a schematic diagram of an adjustment and limiting mechanism according to an embodiment of the present application.

[0034] Numbers in the figure

[0035] first measuring part 1, first dynamometer 11, first lower connecting rod 12, first upper connecting rod 13,

[0036] The second measuring part 2, the second dynamometer 21, the second lower connecting rod 22, the second upper connecting rod 23,

[0037] force transmission part 3, first connection part 31, corner part 32, second connection part 33,

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

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

[0040] Experimental water pool 7, water pool wall 71, water pool horizontal support 72, water pool vertical support 73,

[0041] Measuring device 8,

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

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

[0044] In addition, various components in the drawings are enlarged or reduced in size for ease of understanding, but this practice is not intended to limit the scope of protection of the present application.

[0045] Words importing the singular also include the plural and vice versa.

[0046] In the description of the embodiments of the present application, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the products of the embodiments of the present application are usually placed when in use, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, in the description of the present application, in order to distinguish different units, the words first, second, etc. are used in this specification, but these are not limited by the order of manufacture, nor can they be understood as indicating or implying relative importance, and their names may be different in the detailed description and claims of the present application.

[0047] The vocabulary in this specification is used to illustrate the embodiments of the present application, but is not intended to limit the present application. It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, an indirect connection through an intermediate medium, or a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in this application can be specifically understood.

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

[0049] In order to explain the technical solution of the present application in detail, the method of measuring the force of internal solitary waves on underwater targets in existing water tank experiments is first introduced.

[0050] Figure 1 A solution for measuring the internal solitary wave force is shown in which a plurality of force sensors are arranged on the surface of an underwater target 9, wherein the underwater target 9 may be a scaled-down model of a real underwater submersible, such as Figure 1 As shown, pressure sensors are arranged at the measuring point 901 in front of the underwater target 9, the measuring point 902 on the side and the measuring point 903 above the underwater target 9, respectively, to obtain the components of the internal solitary wave force in each direction on the underwater target 9. However, this measurement scheme has the following problems to be overcome in the actual force measurement process:

[0051] 1) Since the sensors are arranged at various places on the outer surface of the underwater target 9, the measured results are not the forces acting 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 outer shape of the underwater target 9 is irregular, it is necessary to ensure that the force directions of each sensor are orthogonal to each other, which requires cumbersome calibration or the addition of additional attitude measurement devices such as gyroscopes, 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 the action position is often one order of magnitude greater than the horizontal force along the propagation direction. At the same time, the horizontal force along the propagation direction is significantly greater than the force in another horizontal direction perpendicular to it. Figure 1 In the arrangement shown, the force components of the internal solitary waves measured at the three measurement points 901, 902, and 903 have the following relationship:

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

[0054] Obviously, if a single-component force sensor of the same specification is selected, when it meets the resolution requirements, it can achieve the smaller force such as F 901 or F 902 When the precise measurement of F 903 The measuring range may have been exceeded. On the contrary, if the safety of the measuring range is given priority, the precise measurement of the tiny components of the force may not be satisfied.

[0055] 3) In this solution, multiple sensors are placed directly in liquids such as oil and water, which not only greatly increases the probability of sensor damage, but also is not conducive to flexible adjustment of the depth of underwater targets;

[0056] Apart from Figure 1 In addition to the scheme shown, there is also a technical scheme in which a multi-component force sensor is directly set inside the underwater target 9, for example, at the center of mass 91, so as to directly collect the three orthogonal components of the internal solitary wave force there. 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, and is therefore called a six-component force sensor.

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

[0058] There are many factors that affect the accuracy of the six-component force sensor. The most important reason is inter-dimensional coupling. In physics, it refers to the phenomenon that two or more systems or two forms of motion influence each other and even combine through interaction. The input signal in each of the six channels in the six-component force sensor will affect the output signal of other channels. Therefore, it is almost impossible to control only one output with one input without affecting other channels. Therefore, the original signal collected by the multi-component force sensor must undergo a decoupling operation to eliminate the coupling between signals in each direction.

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

[0060] However, as analyzed above, since the sizes of the three orthogonal components of the internal solitary wave differ by orders of magnitude, the multi-component force sensor needs to achieve high-precision measurement within a range that spans orders of magnitude. Therefore, if structural decoupling is used, it is necessary to customize the multi-component force sensor separately according to the range and accuracy indicators in each direction; if mathematical matrix operation decoupling is used, the cross-order of magnitude differences in signals in each direction will have a great impact on the matrix operation accuracy, and may even make it impossible to obtain a stable solution.

[0061] In addition, since the expensive multi-component force sensor needs to be placed below the liquid surface of a mixed liquid such as water and oil, in order to reduce the probability of damage to the multi-component force sensor, it is obvious that higher requirements are placed on the watertight structure of the underwater target 9.

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

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

[0064] The experimental water pool 7 can be constructed using methods known to those skilled in the art. For example, a frame structure of the water pool can be constructed by using a plurality of horizontal water pool supports 72 and vertical water pool supports 73. Various watertight materials are used as the water pool wall 71 and the pool bottom in the frame structure to obtain the experimental water pool 7. Figure 2The figure shows an experimental water pool 7 of a long strip structure extending in the X-axis direction, one end of which is provided with a wave-making mechanism, by which an internal solitary wave that propagates unidirectionally in the X-axis direction can be generated at the interface between two liquids. When the internal solitary wave passes through an underwater target 9, the internal solitary wave force exerted on the underwater target 9 below the liquid level in the experimental water pool 7 can be measured by a measuring device 8. A wave-breaking mechanism is provided at the other end of the experimental water pool 7 to prevent the internal solitary wave from propagating in the opposite direction in the experimental water pool.

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

[0066] The first measuring part 1 comprises a first upper connecting rod 13, a first dynamometer 11 and a first lower connecting rod 12 which are sequentially connected along the Z-axis direction. When in use, the first lower connecting rod 12 is connected to the center of mass 91 of the underwater target 9. The first dynamometer 11 is used to measure the force along the Z-axis direction to obtain the force of the internal solitary wave on the underwater target in the Z-axis direction.

[0067] The second measuring part 2 comprises a second upper connecting rod 23, a second dynamometer 21 and a second lower connecting rod 22 connected in sequence along the θ angle direction, wherein the θ angle direction is a direction deviated from the Z axis by an angle θ in the XZ plane, and the second dynamometer 21 is used to measure the force in the θ angle direction and thus obtain the force of the internal solitary wave on the underwater target in the X-axis direction;

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

[0069] The force transmission part 3 is connected to the ends of the first upper connecting rod 13 and the second lower connecting rod 22 respectively, and is used to rigidly connect the first measuring part 1 and the second measuring part 2 so that all the forces acting on the center of mass 91 can be transmitted to the second dynamometer 21 for collection.

[0070] The support part 4 is arranged above the experimental water pool 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 a plurality of longitudinal brackets, a transverse support unit 42 composed of a plurality of transverse brackets, a vertical support unit 43 composed of a plurality of vertical brackets, and an upper top plate 44 arranged above the transverse support unit 42. The units cooperate with each other and are fixedly connected above the experimental water pool 7.

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

[0072] When the internal solitary wave propagates along the X-axis direction to the underwater target 9, the underwater target 9 will be simultaneously subjected to a vertical force F along the Z-axis direction (vertical direction). z , and the horizontal force F along the X-axis (the direction of propagation of the internal solitary wave) x The force of the internal solitary wave on the underwater target 9 can be represented by the force 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 part 1 is fixedly connected to the mass center 91 and the other end is fixedly connected to the first dynamometer 11, the force received at the mass center 91 is completely transmitted to the first dynamometer 11 through the first lower connecting rod 12 for collection. At this time, the force received at the first dynamometer 11 can be decomposed into a first vertical force F along the Z-axis direction. z ′1 and the first horizontal force F along the X-axis x '1, since the first dynamometer 11 is a unidirectional force dynamometer, it is used to measure the first vertical force F z '1, when the first dynamometer 11 is subjected to a force other than the measurement direction (i.e., the Z-axis direction) (i.e., F x ′1) does not affect the measurement accuracy, that is, in an ideal state, the vertical force F acting on the underwater target 9 along the Z-axis direction can be obtained by the following formula (1): z :

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

[0075] Since the second measuring part 2 is rigidly connected to the first measuring part 1 through the force transmission part 3, the force applied to the center of mass 91 is also transmitted to the second dynamometer 21 for collection. In this application, the second measuring part 2 is set to the angle direction of θ, that is, it deviates from the angle direction of θ relative to the Z axis in the XZ plane, such as Figure 5 As shown, the force on the second dynamometer 21 can be decomposed into a second vertical force F along the angle θ. z ′2 and the second horizontal force F perpendicular to the angle θ x '2, in addition, it is also subjected to a torque M1'. The second dynamometer 21 is used to measure the force along the angle θ 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 dynamometer 21 is F z′2, through the above formula (1) and formula (2), the vertical force F acting on the underwater target 9 along the X-axis direction can be calculated by the following formula (3): x :

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

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

[0080] As described above, for the first measuring part 1, the torque M′1 received by the first dynamometer 11 can be calculated according to the following formula (4):

[0081] M′1=F′ x1 ×L1=F x ×L1 (4);

[0082] Where L1 is the first force arm, i.e., the distance from the first dynamometer 11 to the underwater target mass center 91. As described in the background technology, the horizontal force generated by the internal solitary wave is often small, and is one order of magnitude different from the vertical force. Therefore, the above F′ x1 Much smaller than F′ z1 , when F′ z1 When the torque M′1 is within the measuring range of the first dynamometer 11, it must be within the torque limit of the first dynamometer 11, so it will not affect its safety and measurement accuracy. Therefore, the internal solitary wave force in the Z-axis direction on the underwater target 9 can be directly obtained more accurately through the measurement reading of the first dynamometer 11. Obviously, the torque M′1 is related to F′ x1 In addition to being related, it is also related to the first force arm L1. The closer the distance is, the smaller the torque M′1 received by the first dynamometer 11 is, and the more accurate the measurement result is. However, if the first dynamometer 11 is installed at the center of mass of the underwater target 9, the first dynamometer 11 needs to be watertight, which obviously puts higher requirements on the watertight structure of the underwater target 9. Therefore, in some preferred embodiments, the first dynamometer 11 is arranged at a position 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 part 2, the torque M′2 it receives can be calculated by the following formula (5):

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

[0085] Wherein, L2 is the second force arm, i.e., the distance from the second dynamometer 21 to the inflection point A where the first measuring part 1 and the second measuring part 2 intersect. By analyzing formula (5), it can be seen that the smaller the value of angle θ and L2, the smaller the value of M′2, and the smaller the influence of torque M′2 on the accuracy of the second dynamometer 21. However, since the measuring device itself still has other inevitable system errors, as described in the background technology, F x is often small, so the systematic error to F x The smaller the θ value, the greater the influence of F x The proportion of F in the second dynamometer x The smaller sinθ is, the greater the impact of the system error is, so it is necessary to select a suitable θ angle according to actual needs. Preferably, the θ angle is increased as much as possible while satisfying that M′2 is less than its torque limit to reduce the impact of the system error.

[0086] Therefore, the present application further optimizes the structure and position setting of the second measuring part 2. On the one hand, it can make the torque M′2 in the non-measurement direction received by the second dynamometer 21 smaller than its torque limit so as to maintain the accuracy of its measurement results. 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 solitary wave that the water pool 7 can provide can be determined based on experience. x，max , maximum vertical force F z，max , according to the maximum vertical force F z，max The torque limit of the preselected dynamometer and the value of the second force arm L2 determine the value range of θ, such as when the maximum horizontal force F x，max and the maximum vertical force F z，max When the torque limits of the selected dynamometer are 0.25Nm and the value of the second force 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 dynamometer does not exceed the torque limit, and the measurement result is accurate.

[0088] Specifically, the setting of the angle θ is achieved through the specific structure of the force transmission part 3. Figure 6The specific structure of the force transmission part 3 in some embodiments of the present application is shown, which includes an integral connection member composed of a first connection part 31, a corner part 32 and a second connection part 33. The first connection part 31 and the second connection 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 ends of the second lower connecting rod 22 are respectively inserted into the fixing grooves at both ends to achieve fixed connection. The angle of the corner part 32 is 180-θ°, so as to achieve the connection of the second lower connecting rod 22 in the direction of the deflection θ angle relative to the first upper connecting rod 13; specifically, the fixing groove and the rod can be connected by threaded connection or interference fit. When in use, the change of the θ angle can be achieved by replacing the force transmission part 3 with different angles.

[0089] In addition to optimizing the setting of the angle θ, the second force arm L2 can also be optimized. In some preferred embodiments, Figure 7 As shown, when an integrated connecting piece type force transmission part 3 is adopted, 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 dynamometer 21. The length of the second lower connecting rod 22 is set to enable the second dynamometer 21 to contact the second connecting part 33, that is, by reducing the second force arm L2 to further reduce the influence of the second torque M2′ on the measurement result of the second dynamometer 21, the measurement accuracy of the second dynamometer 21 is improved; in addition, reducing the second force arm L2 can also increase the angle θ while meeting the measurement accuracy requirements of the second dynamometer 21, thereby reducing the influence of system errors.

[0090] In addition, in order to measure the force of the internal solitary wave at different positions in the experimental water pool 7 and to better study the characteristics of the internal solitary wave, the applicant has further improved the above-mentioned measuring device 8.

[0091] In some preferred embodiments, the support portion 4 is movably connected to the experimental water pool 7, so that the longitudinal support unit can slide along the experimental water pool 7 along the X-axis direction; in some preferred embodiments, the upper top plate 44 is movably connected to other support units, so that it can slide relative to the experimental water pool 7 along the Y-axis direction; so as to achieve the ability to measure the 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 formed by the first lower connecting rod 12 being composed of two mutually sleeved rods, that is, one of the rods is set in the form of a hollow cylindrical tube so that it can be sleeved on the outside of the other, and the two have mutually matching stud structures and screw hole structures, and the telescopic degree between the two is adjusted by rotation; in some other embodiments, the length-adjustable connecting rod is formed by the first lower connecting rod 12 being composed of two mutually sleeved rods, one of the rods is provided with a plurality of through holes arranged at intervals along the axial direction, and the other rod is provided with a ball that can be pressed and bounces up after the pressing is released, and when the two rods move axially relative to each other, the ball bounces up after entering a through hole, and the positions of the two rods are limited, thereby achieving the adjustable length.

[0093] In some preferred embodiments, the force transmission part 3 can also be a hinged structure, so that the appropriate angle θ can be adjusted according to the rapid changes of 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 arranged at the ends of the first upper connecting rod 13 and the second lower connecting rod 22, and bolts connected thereto.

[0094] In some preferred embodiments, an adjustment limit mechanism 5 is further included, which is detachably connected to the second upper connecting rod 23 and is used to limit the second upper connecting rod 23. The second upper connecting rod 23 is provided with a scale line. When in use, different measurement positions can be changed by adjusting the limit positions of the second upper connecting rod 23 and the adjustment limit mechanism 5. Figure 8 As shown, the adjustment limit mechanism 5 in some embodiments of the present application includes a first limit block 51 and a second limit block 52, which are rotatably connected to each other; wherein the first limit block 51 is fixedly connected to the support part 4, and the second limit block 52 is rotatably connected to one side of the first limit block 51 along the Y-axis direction, and its rotation direction is parallel to the XZ plane; further, a through hole 521 matching the second upper connecting rod 23 and a fastening structure 522 are provided in the second limit block 52, and specifically, the fastening structure 522 is a top screw type; the positioning of the second measuring part 2 and its rotation in the XZ plane can be achieved by adjusting the limit mechanism 5.

[0095] Furthermore, the adjustment and limiting mechanism 5 can be slidably connected to the support unit of the support part 4. Specifically, the slidable connection can be achieved by setting a sliding groove and 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 cooperates with the hinge structure of the force transmission part 3 and the adjustment limit 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 repeated here.

[0097] In some preferred embodiments, the support part 4 also includes auxiliary positioning structures respectively arranged 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 sleeved at the front and rear of the underwater target 9. The two auxiliary connecting rods 461 respectively penetrate the lateral bracket 42 and the upper top plate 44 matched therewith, and the height can be adjusted in the vertical direction and limited by the joint. The auxiliary positioning structure can be used to assist in adjusting the underwater target 9 to the expected depth and maintaining its direction when adjusting the length of the first lower connecting rod 12.

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

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

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

[0101] S2 creates an internal solitary wave in the experimental pool 7;

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

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

[0104] Specifically, the force measured by the first measuring part 1 in S3 is F′ z1 The vertical force F acting on the underwater target 9 can be obtained by 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 is x According to the measurement result F of the first measuring unit 1 z '1. Measurement result F of the second measuring unit 2 z '2 is obtained by the following formula (3):

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

[0108] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. An internal solitary wave force measuring device, used to measure the internal solitary wave force exerted on an underwater target arranged in an experimental water pool, characterized in that: It comprises 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 part (1) comprises a first upper connecting rod (13), a first dynamometer (11) and a first lower connecting rod (12) which are sequentially connected along the Z-axis direction; when in use, the first lower connecting rod (12) is connected to the center of mass (91) of the underwater target (9); and the first dynamometer (11) is used to measure the force along the Z-axis direction to obtain the force of the internal solitary wave on the underwater target in the Z-axis direction; The second measuring part (2) comprises a second upper connecting rod (23), a second dynamometer (21) and a second lower connecting rod (22) connected in sequence along an angle θ direction, wherein the angle θ direction is a direction deviating from the Z axis by an angle θ in the XZ plane, and the second dynamometer (21) is used to measure the force in the angle θ direction and thereby obtain the force of the internal solitary wave on the underwater target in the X-axis direction; The angle θ is set so that the torque M2 on the second dynamometer (21) is ′ Less than the torque limit of the second dynamometer (21).

2. The internal solitary wave force measurement device according to claim 1, characterized in that: The force transmission part (3) comprises a first connection part (31), a corner part (32) and a second connection part (33); the first connection part (31) and the second connection part (33) are respectively provided with a first fixing groove and a second fixing groove which 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 measurement 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 dynamometer (21). The length of the second lower connecting rod (22) is set to enable the second dynamometer (21) to contact the second connecting portion (33).

4. The internal solitary wave force measurement device according to claim 1, characterized in that: The second lower connecting rod (22) and the first upper connecting rod (13) are hingedly connected via a force transmission part (3).

5. The internal solitary wave force measuring device according to claim 4, characterized in that: The force transmission part (3) comprises through holes respectively arranged at the ends of the first upper connecting rod (13) and the second lower connecting rod (22) and bolts matched and connected thereto.

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

7. The internal solitary wave force measurement device according to claim 6, characterized in that: The adjustment limit mechanism (5) comprises a first limit block (51) and a second limit block (52), wherein the first limit block (51) is slidably connected to the support portion (4) along the X-axis, and the second limit block (52) is rotatably connected to one side of the first limit block (51) along the Y-axis direction, and its rotation direction is parallel to the XZ plane, and the second limit 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 measurement device according to claim 1, characterized in that: The first lower connecting rod (12) and / or the second upper connecting rod (23) are connecting rods with adjustable length.

9. The internal solitary wave force measurement device according to claim 1, characterized in that: The support part (4) comprises a longitudinal support unit (41), a transverse support unit (42), a vertical support unit (43) which cooperate with each other, and an upper top plate (44) arranged above the transverse support unit. When in use, the support part (4) can be slidably arranged above the experimental water pool.

10. The internal solitary wave force measuring device according to claim 9, characterized in that: When in use, the longitudinal support unit (41) of the support portion (4) can slide relative to the experimental water pool 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 pool along the Y-axis direction.

11. The internal solitary wave force measuring device according to claim 10, characterized in that: The support portion (4) also includes an auxiliary positioning structure for being arranged at the front and rear of the underwater target (9), the auxiliary positioning structure including at least two auxiliary connecting rods (461), each of the auxiliary connecting rods (461) being fixedly connected to the collar (462), the two auxiliary connecting rods (461) respectively passing through the lateral bracket (42) and the upper top plate (44) matched therewith, the height of which can be adjusted in the vertical direction, and the position is limited by the joint.

12. An internal solitary wave force measurement system, comprising an experimental water pool (7), a wave-making mechanism, a wave-breaking mechanism and an underwater target (9), wherein the experimental water pool is filled with at least two liquids of different densities, the wave-making mechanism is used to create an internal solitary wave propagating in the two liquids of different densities, and the wave-breaking mechanism is used to eliminate the internal solitary wave, characterized in that: It also includes an internal solitary wave force measuring device as described in any one of claims 1 to 11, which is used to measure the internal solitary wave force exerted on the underwater target.

13. A method for measuring internal solitary wave force, operated using the internal solitary wave force measurement system according to claim 12, characterized in that: The following steps are involved: S1 assembling and positioning the devices so that the first lower connecting rod (12) is connected to the center of mass (91) of the underwater target (9); S2 creates an internal solitary wave in the experimental water pool (7); S3 measures the force in the vertical direction and the force in the θ angle direction exerted on the underwater target (9) by means of the first measuring unit (1) and the second measuring unit (2) respectively; S4 calculates the horizontal force acting on the underwater target (9) through force balance decomposition based on the measurement results of the first measurement unit (1) and the second measurement unit (2) in S3.

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