Depth-adjustable internal solitary wave force measurement system and measurement method

Abstract

The present application provides a depth-adjustable internal solitary wave force measurement system and measurement method, the measurement system includes an experimental pool, a wave-making mechanism, a wave-breaking mechanism, an underwater target and a measurement device, the measurement device includes a first measurement part, a second measurement part, a force transmission part and a support structure; the first measurement part includes an upper connecting rod, a first dynamometer, a first lower connecting rod and a second lower connecting rod, the lower end of the second lower connecting rod is fixedly connected to the underwater target at its center of mass and the distance from the lower end of the second lower connecting rod to the upper end of the upper connecting rod is adjustable; the second measurement part includes a front connecting rod, a second dynamometer and a rear connecting rod; the force transmission part includes a connecting part and a virtual connection part, wherein the virtual connection part has a virtual connection channel that runs through in the vertical direction, and one of the upper connecting rod, the first lower connecting rod and the second lower connecting rod passes through the virtual connection channel and is virtually connected with the virtual connection part. The measurement device provided by the present application can accurately measure the internal solitary wave force exerted on the underwater target at different depths.

Description

Technical Field

[0001] The present application belongs to the technical field of internal solitary wave experiments, and in particular, relates to a depth-adjustable internal solitary wave force measurement system and measurement 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 significantly during its propagation, which will have a great impact on the stability and controllability of the submerged body.

[0003] Internal solitary wave tank experiments are an important means to study the influence of internal solitary waves on the hydrodynamic performance of underwater submersibles. Currently, quite a number of schemes for internal solitary wave tank experiments have been made public. For example, three pressure sensors are arranged on the head, middle and side of the submersible model to measure the forces in three directions respectively, or multi-component force sensors are used to perform multi-component measurements of the internal solitary wave force.

[0004] However, the above-mentioned existing technical solutions for internal solitary wave tank experiments are either unable to simultaneously measure the multi-directional forces at the center of mass of the underwater target, or require the separate customization of expensive multi-component force sensors. At the same time, it is impossible to conveniently and flexibly adjust the experimental depth of the underwater target in an experimental tank filled with various media such as oil and water to meet the needs of measuring the internal solitary wave forces at different depths. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present application provides a depth-adjustable internal solitary wave force measurement system through an embodiment, including an experimental water pool, a wave-making mechanism, a wave-breaking mechanism, an underwater target and a measuring device, wherein the experimental water pool is filled with at least two liquids with different densities, the wave-making mechanism is used to create internal solitary waves in the experimental water pool, and the wave-breaking mechanism is used to eliminate the internal solitary waves; the measuring device includes a first measuring part, a second measuring part, a force transmission part and a supporting structure arranged above the experimental water pool; the first measuring part includes an upper connecting rod, a first dynamometer, a first lower connecting rod and a second lower connecting rod connected in sequence along the vertical direction, wherein the upper end of the upper connecting rod is rotatably connected to the supporting structure, and the direction of its rotation axis is perpendicular to the vertical direction at the same time. In the direction of propagation of the internal solitary wave, the lower end of the second lower connecting rod extends into the underwater target and is fixedly connected to the underwater target at its center of mass, and the distance from the lower end of the second lower connecting rod to the upper end of the upper connecting rod is adjustable; the second measuring part comprises a front connecting rod, a second dynamometer and a rear connecting rod which are sequentially connected along the propagation direction of the internal solitary wave, and the rear connecting rod is detachably fixedly connected to the supporting structure; the force transmitting part comprises a connecting part and a virtual connecting part, wherein the connecting part is fixedly connected to the front connecting rod at one end facing the front connecting rod, and is fixedly connected to the virtual connecting part at one end facing away from the front connecting rod, and the virtual connecting part has a virtual connecting channel which runs through in the vertical direction, and one of the upper connecting rod, the first lower connecting rod and the second lower connecting rod passes through the virtual connecting channel and is virtually connected to the virtual connecting part.

[0006] Optionally, the second lower connecting rod is sleeved with the first lower connecting rod and can slide along the axial direction of the first lower connecting rod.

[0007] Optionally, there are multiple second lower connecting rods with different lengths from each other, and the multiple second lower connecting rods are selectively connected to the first lower connecting rod and the underwater target.

[0008] Preferably, the distance from the rotation axis of the upper connecting rod to the center of mass of the underwater target is 4 to 12 times the distance from the rotation axis of the upper connecting rod to the force transmission part.

[0009] Preferably, the virtual connection portion is configured as a circular ring having a circular or elliptical cross section, or the virtual connection portion is configured as a rectangular ring having a wedge-shaped cross section.

[0010] Furthermore, the support structure includes a longitudinal support unit, a transverse support unit, a vertical support unit, an upper top plate arranged above the transverse support unit, and a side plate arranged on the side of the vertical support unit facing the propagation direction of the internal solitary wave; a hinged portion is provided on the lower surface of the upper top plate, and the hinged portion includes a hinge seat, a rotating shaft and a bearing, the hinge seat is fixedly connected to the lower surface of the upper top plate, the rotating shaft is fixedly connected to the upper end of the upper connecting rod, and is rotatably connected to the hinge seat through the bearing; an adjustment limit mechanism is provided on the side plate, the rear connecting rod passes through the side plate, and the horizontal position of the rear connecting rod relative to the side plate is limited by the adjustment limit mechanism.

[0011] Preferably, the side plate is further provided with a sliding groove extending in the vertical direction and penetrating the side plate, so as to enable the second measuring part and the force transmitting part to slide in the vertical direction relative to the side plate.

[0012] Preferably, the measurement system also includes an auxiliary positioning structure, which includes at least two auxiliary connecting rods with adjustable height in the vertical direction, and a ring fixedly connected to each auxiliary connecting rod, and the rings are respectively mounted on the front and rear of the underwater target.

[0013] Preferably, the measuring system also includes a calibration device, which is configured to determine the measurement error of the first measuring part and the magnification of the second measuring part in the measuring device by applying a standard reference force to the lower end of the second lower connecting rod in the vertical direction and the horizontal direction respectively.

[0014] The present application also provides an internal solitary wave force measurement method through an embodiment, using the aforementioned depth-adjustable internal solitary wave force measurement system to measure the internal solitary wave force exerted on an underwater target at different depths, and the measurement method comprises the following steps:

[0015] S100, assembling the support structure, the first measuring part, the second measuring part, and the force transmission part, and adjusting the positions of the first measuring part, the second measuring part, and the force transmission part so that the force transmission part is in virtual contact with the first measuring part;

[0016] S200, for each measured depth of the underwater target, execute steps S210 to S260 respectively:

[0017] S210, adjusting the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod based on the measured depth;

[0018] S220, fixedly connecting the lower end of the second lower connecting rod to the center of mass of the underwater target, and adjusting the counterweight so that the underwater target is in a state of gravity and buoyancy balance in the experimental water pool;

[0019] S230, generating an internal solitary wave in the experimental water pool;

[0020] S240, respectively performing measurements in a vertical direction and a horizontal direction by the first measuring unit and the second measuring unit when the internal solitary wave passes through the underwater target;

[0021] S250, determining the vertical force exerted on the center of mass of the underwater target by the internal solitary wave based on the measurement result of the first measurement unit;

[0022] S260, determining the horizontal force exerted by the internal solitary wave on the center of mass of the underwater target based on the measurement result of the second measuring unit and the magnification, wherein the magnification is determined based on the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmission unit and the upper end of the upper connecting rod.

[0023] Preferably, step S212 is further included between steps S210 and S220:

[0024] Whether the magnification is within a preset magnification range is determined based on the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmitting part and the upper end of the upper connecting rod. If not, the positions of the second measuring part and the force transmitting part are adjusted until the magnification is within the preset magnification range.

[0025] Preferably, a calibration step is also included before step S200, and the calibration step is used to determine the measurement error of the first measuring part and the change of the magnification with the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod or the distance between the force transmission part and the upper end of the upper connecting rod.

[0026] The embodiments of the present application provide a variable-depth internal solitary wave force measurement system and method: by setting a first measuring part 1 with adjustable length and directly connecting the lower end of the first measuring part 1 to the center of mass 91 of the underwater target 9, and connecting the second measuring part 2 to the first measuring part 1 in the horizontal direction, it is possible to directly obtain the force at the center of mass, avoiding the problem that the acquisition directions of each sensor are difficult to align orthogonally when the sensor is placed on the irregular surface of the underwater target 9, and the depth of the underwater target 9 can be flexibly adjusted by adjusting the positions of the two lower connecting rods relative to each other; at the same time, the vertical force is directly collected by using the virtual connection between the force transmission part 3 and the first measuring part 1, and at the same time, the first measuring part 1 is rotatably connected to the upper top plate 44, and the second measuring part 2 and the force transmission part 3 are fixed at a suitable position. The horizontal force is collected by amplifying the fixed connection method, so that the magnitudes of the components of the internal solitary wave force in each direction are in a consistent magnitude range, so that the measurement can be completed using high-precision single-component force sensors with multiple ranges and consistent accuracy, without the need to select multiple sensors of different specifications. It also avoids the problem that when only one multi-component force sensor is set at the center of mass 91, due to the magnitude differences of the force components in each direction, in order to ensure that the errors of each component obtained by decoupling are controlled within an acceptable range, a wide-range and high-precision multi-component force sensor needs to be customized separately; in addition, since direct measurement in the vertical direction and horizontal transfer and amplification measurement are adopted, the dynamometers for measuring the force can be set above the liquid surface, which is convenient for installation and use, and greatly reduces the probability of equipment damage caused by placing the sensor in the liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the arrangement of sensors for testing the internal solitary wave force on an underwater target;

[0028] Figure 2 A schematic diagram of the layout of a depth-adjustable internal solitary wave force measurement system provided according to an embodiment of the present application;

[0029] Figure 3 A schematic diagram of the structure of a measuring device according to an embodiment of the present application is provided;

[0030] Figure 4 for Figure 3 An enlarged schematic diagram of the middle circle A;

[0031] Figure 5 A schematic diagram of a partial structure of a measuring device provided according to an embodiment of the present application;

[0032] Figure 6 A side view of a measuring device provided according to an embodiment of the present application;

[0033] Figure 7 for Figure 5 Enlarged schematic diagram of the middle circle B;

[0034] Figure 8 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0035] Fig. 9 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0036] Fig.10 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0037] Fig.11 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0038] Fig.12 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0039] Fig.13 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0040] Fig.14 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0041] Fig.15 A side view of a force transmission portion provided according to an embodiment of the present application;

[0042] Fig.16 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0043] Fig.17 A side view of a force transmission portion provided according to an embodiment of the present application;

[0044] Fig.18 A schematic diagram of a partial structure of a measuring device provided according to an embodiment of the present application;

[0045] Fig.19 It is a flow chart of the internal solitary wave force measurement method provided according to an embodiment of the present application;

[0046] Fig. 20 is an implementation flow chart of step S212 provided according to an embodiment of the present application;

[0047] Fig.21 A schematic diagram of the layout of a calibration device provided according to an embodiment of the present application;

[0048] Fig. 22 for Fig.21 An enlarged schematic diagram of the middle circle C;

[0049] Fig.23A schematic diagram of the layout of pulleys provided according to an embodiment of the present application;

[0050] Fig.24 A schematic diagram of a calibration result of a vertical measurement error provided according to an embodiment of the present application;

[0051] Fig.25 A schematic diagram of the calibration result of the horizontal magnification provided according to an embodiment of the present application;

[0052] Fig.26 is a schematic diagram of the vertical force of an internal solitary wave on an underwater target measured according to an embodiment of the present application;

[0053] Fig. 27 It is a schematic diagram of the horizontal force of the internal solitary wave on the underwater target measured according to the embodiment of the present application.

[0054] Numbers in the figure

[0055] first measuring part 1, upper connecting rod 11, first lower connecting rod 12-1, second lower connecting rod 12-2, first dynamometer 13, connecting rod joint 14, second measuring part 2, front connecting rod 21, rear connecting rod 22, second dynamometer 23, force transmission part 3, virtual connection channel 301, virtual connection part 31-1, virtual connection part 31-2, virtual connection part 31-3, virtual connection part 31-4, connecting part 32, protrusion 33, supporting structure 4, longitudinal bracket 41, transverse bracket 42, vertical bracket 43, upper top plate 44, Articulated seat 441, rotating shaft 442, bearing 443, side plate 45, adjustment limit mechanism 451, sleeve 4511, limit pin 4512, slide groove 452, auxiliary connecting rod 461, collar 462, calibration device 5, standard weight 51, standard weight 52, tray 53, pulley 54, experimental water pool 7, water pool wall 71, water pool horizontal bracket 72, water pool vertical bracket 73, measuring device 8, underwater target 9, center of mass 91, measuring point 901, measuring point 902, measuring point 903. DETAILED DESCRIPTION

[0056] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0057] For ease of understanding, various components on the drawings are enlarged or reduced, but this practice is not intended to limit the scope of protection of this application. Words in the singular form also include the plural meaning, and vice versa.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] As described in the background technology, water tank experiments are an important means to study the effects of internal solitary waves on underwater submersibles. Obviously, accurate measurement of the forces acting on underwater targets placed in the experimental water tank is a prerequisite and key to effective analysis of the mechanism of action of internal solitary waves. Figure 1 A scheme for measuring the force of an internal solitary wave in which a plurality of force sensors are arranged on the surface of an underwater target 9 is shown, wherein the underwater target 9 may be a scaled-down model of a real underwater submersible. Without loss of generality, in an embodiment 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.

[0062] like 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:

[0063] 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;

[0064] 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:

[0065] F 903 >>F 901 >>F 902 ,

[0066] 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.

[0067] 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;

[0068] 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 main axes, and is therefore called a six-component force sensor.

[0069] The measurement principle of the six-component force sensor is based on the bridge balance of the strain gauge. The force and torque are 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 force and torque applied to the object can be calculated.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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, there is also the problem of equipment damage and the inability to conveniently adjust the depth of the underwater target.

[0074] It can be seen that how to achieve accurate, low-cost and convenient measurement of internal solitary wave forces at different depths in a water tank experimental environment is an urgent problem to be solved.

[0075] In order to solve the above problems, the present application provides a depth-adjustable internal solitary wave force measurement system through an embodiment. Figure 2The overall structure diagram of the measurement system is shown in Figure 2 As shown, the measurement system includes an experimental water pool 7, a measurement device 8, an underwater target 9 (indicated by dotted lines in the figure), and a wave-making mechanism and a wave-breaking mechanism not shown in the figure.

[0076] 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 using multiple horizontal water pool supports 72 and vertical water pool supports 73. Various types of watertight materials are used as water pool walls 71 and a bottom of the water pool within the frame structure to obtain the experimental water pool 7.

[0077] The experimental pool 7 is generally used as follows Figure 2 The long strip structure extending along the X-axis direction shown in the figure has a wave-making mechanism at one end, which can generate an internal solitary wave that propagates unidirectionally along the X-axis direction at the interface between the two liquids. When the internal solitary wave passes through the underwater target 9, the internal solitary wave force on the underwater target 9 below the liquid level in the experimental water pool 7 can be measured by the measuring device 8. The other end of the experimental water pool 7 is provided with a wave-breaking mechanism to prevent the internal solitary wave from propagating in the opposite direction in the experimental water pool.

[0078] Figure 3 shows the specific structure of the measuring device 8 in some embodiments, Figure 4 right Figure 3 The circle A in the figure is enlarged. Figure 5 FIG. 8 is a schematic diagram showing a partial structure of a measuring device 8 in some other embodiments. Figure 6 shows a side view of a measuring device 8 in some embodiments, Figure 7 Zoomed in Figure 6 Circle B in the figure. The following combination Figures 3 to 7 , the measuring device 8 is described in detail.

[0079] As shown in the figure, the measuring device 8 includes a first measuring part 1, a second measuring part 2, a force transmission part 3 and a supporting structure 4 arranged above the experimental water pool.

[0080] The support structure 4 is used to provide positioning and support for measuring components such as the first measuring part 1, the second measuring part 2 and the force transmission part 3, and includes a longitudinal support unit composed of multiple longitudinal brackets 41, a transverse support unit composed of multiple transverse brackets 42, a vertical support unit composed of multiple vertical brackets 43, and an upper top plate 44 arranged above the transverse support unit and a side plate 45 arranged on the side of the vertical support unit facing the propagation direction of the internal solitary wave (i.e., the direction indicated by the X-axis arrow). The longitudinal support unit, the transverse support unit and the vertical support unit cooperate with each other and can be arranged above the experimental water pool in a fixed connection manner, or can adopt the movable connection manner of some existing measuring systems, so that the longitudinal support unit can slide along the experimental water pool 7 along the X-axis direction, and the upper top plate above the transverse support unit can slide relative to the experimental water pool along the Y-axis direction. The above specific implementation methods do not deviate from the concept of the technical solution of the present application.

[0081] The first measuring part 1 includes an upper connecting rod 11, a first dynamometer 13, a first lower connecting rod 12-1 and a second lower connecting rod 12-2 which are connected in sequence from top to bottom along the vertical direction, wherein the top end of the upper connecting rod 11 is rotatably connected to the upper top plate 44 through a hinge, and the direction of its rotation axis is the Y-axis direction, that is, it is perpendicular to the vertical direction (Z-axis direction) and the propagation direction of the internal solitary wave (X-axis direction); the lower end of the second lower connecting rod 12-2 extends into the underwater target 9 through threaded connection, interference fit or plug-in, and is fixedly connected to the underwater target 9 at its center of mass 91; the second lower connecting rod 12-2 and the first lower connecting rod 12-1 are connected in a telescopic manner, so that the distance between the lower end of the second lower connecting rod 12-2 and the rotation axis of the upper connecting rod is adjustable.

[0082] The second lower connecting rod 12-2 and the first lower connecting rod 12-1 can be connected telescopically in a variety of ways. For example, one of the first lower connecting rod 12-1 and the second lower connecting rod 12-2 can be set in the form of a hollow cylinder so that it can be sleeved on the outside of the other, and the two have mutually matching stud structures and screw hole structures. The degree of telescopic movement between the two can be adjusted by rotating, thereby adjusting the depth of the underwater target 9 entering the liquid. For example, Figure 3 , Figure 4As shown, a plurality of through holes arranged at intervals along the axial direction are provided on the second lower connecting rod 12-2, and a round ball which can be pressed and bounces up after the pressing is released is provided on the first lower connecting rod 12-1. The second lower connecting rod 12-2 is sleeved on the outside of the first lower connecting rod 12-1. When it moves axially along the first lower connecting rod 12-1, the round ball bounces up after entering a certain through hole, thereby limiting the position of the second lower connecting rod 12-2 relative to the first lower connecting rod 12-1, thereby determining the length of the entire first measuring part 1 (that is, determining the depth of the underwater target 9 below the liquid surface). If it is necessary to change the depth of the underwater target 9, it can also be achieved by pressing the round ball and making it bounce up at other through holes.

[0083] There may also be other ways to adjust the depth of the underwater target 9. For example, in other embodiments, there may be two, three, four or more second lower connecting rods 12-2. The lengths of the second lower connecting rods 12-2 are different, and the upper ends of the second lower connecting rods 12-2 are all provided with stud structures. When measuring the internal solitary wave force, according to the depth at which the underwater target 9 is to be placed, a second lower connecting rod 12-2 of a suitable length is selected from a plurality of second lower connecting rods 12-2, and the lower end of the second lower connecting rod 12-2 is fixedly connected to the underwater target 9, and then the second lower connecting rod 12-2 is fixedly connected to the underwater target 9. Fig. 9 As shown, the threaded connection is achieved with the first lower link 12 - 1 via the link joint 14 .

[0084] The second measuring part 2 includes a front link 21, a second dynamometer 23 and a rear link 22 which are sequentially connected along the propagation direction of the internal solitary wave (X-axis direction), wherein the rear link 22 is detachably fixedly connected to the support structure 4. Specifically, as shown in the figure, an adjustment limit mechanism 451 is provided on the side plate 45. The adjustment limit mechanism 451 is respectively arranged on both sides of the side plate 45, and a sleeve 4511 is protruded from its surface. The rear link 22 passes through the side plate 45 along the sleeve 4511. After it is adjusted to a suitable position relative to the side plate 45 along the X-axis direction, its horizontal position can be limited by a limit pin 4512.

[0085] It should be noted that, without departing from the concept of the present application, those skilled in the art may also use other optional implementations to achieve a rotatable connection between the first measuring part 1 and the support structure 4 relative to the Y-axis, and movement and limitation of the second measuring part 2 relative to the X-axis direction.

[0086] Furthermore, the first measuring part 1 and the second measuring part 2 are connected via a force transmission part 3. As shown in the figure, the force transmission part includes a connecting part 32 and a virtual connection part 31, wherein the connecting part 32 is fixedly connected to the front connecting rod 21 at one end facing the front connecting rod 21, and is fixedly connected to the virtual connection part 31 at one end facing away from the front connecting rod 21. The virtual connection part 31 has a virtual connection channel running through the upper connecting rod 11, the first lower connecting rod 12-1, and one of the second lower connecting rod 12-2 passes through the virtual connection channel and is virtually connected to the virtual connection part 31.

[0087] Figures 8 to 17 Various optional embodiments of the force transmission part 3 are shown. The structure of the force transmission part 3 and the principle of measuring the internal solitary wave force exerted on the underwater target 9 by the first measuring part 1 and the second measuring part 2 through the force transmission part 3 are described in detail below in conjunction with the accompanying drawings.

[0088] Figure 8 , Fig. 9 An optional structure of the force transmission part 3 is shown. As shown in the figure, in this embodiment, the force transmission part 3 includes a virtual connection part 31-1 and a connection part 32, and the two can be made in one piece or fixedly connected by bonding, welding, etc.

[0089] The virtual connection part 31-1 has a virtual connection channel 301 running through it in the vertical direction. The first lower connecting rod 12-1 passes through the virtual connection channel 301 and forms a virtual connection with the virtual connection part 31-1. At the same time, a fixing groove is opened at one end of the connecting part 32 facing the front connecting rod 21. The rightmost end of the front connecting rod 21 can be inserted into the fixing groove and fixedly connected to the connecting part 32 by interference fit or threaded connection.

[0090] In the embodiments of the present application, a virtual connection refers to a connection relationship in which:

[0091] On the one hand, when the central axis of the connecting rod passing through the virtual connection channel coincides with the central axis of the virtual connection channel, the connecting rod passing through the virtual connection channel does not exert a horizontal force on the virtual connection portion;

[0092] On the other hand, when the central axis of the connecting rod passing through the virtual channel does not coincide with the central axis of the virtual channel (generally, when the deviation of the two lines exceeds a preset deviation threshold, it can be determined that the two do not coincide), the connecting rod passing through the virtual channel applies a horizontal force to the virtual joint.

[0093] Combination Figure 8 and Fig. 9, the outer diameter of the first lower connecting rod 12-1 can be set to be slightly smaller than the inner diameter of the virtual connection channel 301, so that when the central axes of the two are in an overlapping state, the lower connecting rod 12-1 does not generate any force along the X-axis direction on the virtual connection part 3 (correspondingly, the first lower connecting rod 12-1 will not be subjected to the friction force in the vertical direction). Once the first lower connecting rod 12-1 undergoes an extremely small movement, resulting in the misalignment of its central axis with the central axis of the virtual connection channel, it will immediately come into actual contact with the virtual connection channel 301 and generate a horizontal force on the virtual connection part 31.

[0094] Combination Figure 6 When the internal solitary wave reaches the underwater target 9 during the propagation process along the X-axis, the underwater target 9 will be simultaneously subjected to a vertical force along the Z-axis direction and a horizontal force along the propagation direction of the internal solitary wave (X-axis direction). 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.

[0095] Since the lower end of the first lower link 12-1 is exactly located at the mass center 91, it is simultaneously subjected to a vertical force F Z and the horizontal force F X , wherein, since the first lower link 12-1 and the force transmission part 3 are in virtual connection, the vertical force F Z is directly transmitted to the first dynamometer 13 and collected by it; the horizontal force F X The lever structure formed by the three fulcrums of the rotating shaft 442, the force transmission part 3 and the mass center 91 is converted into F X 'X and transmitted to the front link 21, and collected by the second dynamometer 23. Obviously, since the distance DH from the rotating shaft 442 to the force transmission part 3 is less than the distance DH+DL from the rotating shaft 442 to the center of mass 91, F X 'X relative to F X It is amplified, and the theoretical value of its amplification factor is (DH+DL) / DH.

[0096] Obviously, after the length from the rotating shaft 442 to the mass center 91 of the underwater target 9 is determined, by reasonably setting the vertical position of the force transmission part 3, the F X 'X adjusted to match F Z The values ​​are in a relatively close range, so that the required range and measurement accuracy of the second dynamometer 23 can be consistent with those of the first dynamometer 13. Therefore, the same type of dynamometer can be selected as the first dynamometer 13 and the second dynamometer 23, which greatly reduces the complexity of equipment selection while ensuring the measurement accuracy.

[0097] For example, in some preferred embodiments, the distance (DH+DL) from the rotation axis of the upper connecting rod 11 (i.e., the axis of the rotating shaft 442) to the mass center 91 of the underwater target 9 can be set to be 4 to 12 times the distance DH from the rotation axis of the upper connecting rod 11 to the force transmission part 3. With this setting, F X 'X Basic and F Z remain at the same order of magnitude, so it can be Z The maximum value is taken as the upper limit of the range, and a dynamometer with accuracy that meets the requirements is selected within this upper limit of the range.

[0098] In the embodiment of the present application, the measurement device 8 of the above structure has the following significant advantages compared with various existing internal solitary wave measurement solutions:

[0099] 1) By providing a first measuring part 1 with adjustable length and directly connecting the lower end of the first measuring part 1 to the center of mass 91 of the underwater target 9, and connecting the second measuring part 2 to the first measuring part 1 in the horizontal direction, the force at the center of mass can be directly obtained, avoiding the problem that the acquisition directions of each sensor are difficult to align orthogonally when the sensor is placed on the irregular surface of the underwater target 9, and the depth of the underwater target 9 can be flexibly adjusted by adjusting the positions of the two lower connecting rods;

[0100] 2) The vertical force is directly collected by virtual connection between the force transmission part 3 and the first measuring part 1, and the horizontal force is amplified by the first measuring part 1 and the upper top plate 44, and the second measuring part 2 and the force transmission part 3 are fixedly connected at a suitable position, so that the magnitude of the components of the internal solitary wave force in each direction is in a consistent magnitude range, so that a high-precision single-component force sensor with multiple ranges and consistent accuracy can be used to complete the measurement, without the need to select multiple sensors of different specifications, and also avoids the problem of setting only one multi-component force sensor at the center of mass 91. Due to the magnitude difference of the force components in each direction, in order to ensure that the errors of each component obtained by decoupling are controlled within an acceptable range, a wide-range high-precision multi-component force sensor needs to be customized separately;

[0101] 3) Due to the use of direct measurement in the vertical direction and horizontal transfer and amplification measurement, the dynamometers for measuring force can be set above the liquid surface, which is easy to install and use, and greatly reduces the probability of equipment damage caused by placing the sensor in the liquid.

[0102] Fig.10Another optional embodiment of the force transmission part 3 is shown. In this embodiment, the cross-sectional shape of the first lower connecting rod 12-1 is a rectangle, and one pair of its four surfaces is perpendicular to the propagation direction of the internal solitary wave, and the other pair of surfaces is parallel to the propagation direction of the internal solitary wave. Accordingly, the cross-sectional shape of the virtual connection channel is also set to a rectangle matching it. The connecting rod passing through the virtual connection channel 301 is set as a rectangular rod, and its surface is oriented toward the propagation direction of the internal solitary wave, which can effectively avoid the twisting of the connecting rod when it is subjected to force, and ensure that the horizontal force transmitted to the second measuring part 2 is as consistent as possible with the propagation direction of the internal solitary wave.

[0103] In some preferred embodiments, a lubricating material such as grease can be coated on the portion of the first lower connecting rod 12-1 passing through the virtual channel 301. The lubricating material will fill the gap between the outer wall of the first lower connecting rod 12-1 and the virtual channel 301, which can effectively avoid the problem of a large gap between the first lower connecting rod 12-1 and the virtual channel 301 due to manufacturing tolerance, thereby causing a large error in the horizontal force measurement result, and can also reduce the error in the vertical force measurement result caused by the additional friction force generated by the virtual channel 301 on the first lower connecting rod 12-1.

[0104] In addition, the structure of the virtual connection portion can be further adjusted to reduce the length of the virtual connection channel 301. The benefit of reducing the length of the virtual connection channel 301 is obvious: since the length of the virtual connection area between the virtual connection channel 301 and the connecting rod passing through it is shortened, it is convenient to more accurately determine the F X For example, in some preferred embodiments, the virtual connection portion 31-2 can be as follows Fig.12 As shown, it becomes thinner in the vertical direction. Particularly preferably, the length of the virtual connection channel 301 corresponding to the virtual connection portion 31 - 2 can be made smaller than the diameter of the front connecting rod 21 .

[0105] The length of the virtual connection channel 301 can be further reduced. Figures 12 to 15 As shown, in the case where the first lower link 12-1 is a rectangular rod, a virtual connection portion 31-3 in the form of a rectangular ring with a wedge-shaped cross section is used, or, as shown in FIG. Fig.16 , Fig.17 As shown in the figure, in the case where the first lower connecting rod 12-1 is a cylindrical rod, a virtual connection portion 31-4 having a circular ring shape is used and connected to the connecting portion 32 through a protrusion 33. When the virtual connection portion of the above structure is used, the length of the virtual connection channel is actually shortened to a minimum, and its side length or diameter D2 is equal to or very slightly greater than the side length or outer diameter D1 of the lower connecting rod 12. At this time, the distance between DH and DL can be measured more accurately, that is, the distance between F and DH can be accurately determined. X Magnification factor.

[0106] Fig.18 In the illustrated embodiment, the first dynamometer 13 is located below the force transmission part 3. When this arrangement is adopted, the connecting rod passing through the virtual channel 301 of the force transmission part 3 is the upper connecting rod 11. At this time, the first lower connecting rod 12-1 is no longer connected to the first dynamometer 13 after passing through the virtual channel 301. The first lower connecting rod 12-1 can transmit the vertical force to the first dynamometer 13 before passing through the force transmission part, thereby reducing the influence of the contact between the connecting rod and the force transmission part on the vertical force measurement result.

[0107] Back to Figure 6 As analyzed above, after changing the length of the second lower link 12-2, F X The magnification factor will also change. In order to ensure that the magnified F X The size of 'X is within the effective range of the second dynamometer 23, such as Figure 5 , Fig.18 As shown, in some preferred embodiments, the side plate 45 is further provided with a slide groove 452 extending in the vertical direction and penetrating the side plate 45, and the rear connecting rod 22 and the adjustment limit mechanism 451 can slide in the vertical direction relative to the side plate 45, thereby driving the entire second measuring part 2 and the force transmission part 3 to slide in the vertical direction, so that DH and DL change at the same time (DH+DL remains unchanged), and finally F X The magnification factor of the method is changed to ensure that it is within a pre-set reasonable method magnification range (such as the range of 4 to 12 times as mentioned above).

[0108] 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.

[0109] In addition, in some preferred embodiments, as shown in the figure, an auxiliary positioning structure can also be set 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 on the front and rear of the underwater target 9. The auxiliary connecting rod 461 and the transverse bracket 42 that cooperates with it can adjust the height in the vertical direction and limit the position through the joint. The auxiliary positioning structure can assist in adjusting the underwater target 9 to the expected depth and maintaining its direction when replacing the second lower connecting rod 12-2 or adjusting the extension of the second lower connecting rod 12-2 relative to the first lower connecting rod 12-1.

[0110] Some embodiments of the present application also provide an internal solitary wave force measurement method, by using the depth-adjustable internal solitary wave force measurement system, the internal solitary wave force exerted on an underwater target at different depths is measured.

[0111] Fig.19 is a flow chart of the measurement method provided according to some embodiments, such as Fig.19 As shown, the measuring method comprises the following steps:

[0112] S100, assembling the support structure, the first measuring part, the second measuring part, and the force transmission part, and adjusting the positions of the first measuring part, the second measuring part, and the force transmission part so that the force transmission part is in virtual contact with the first measuring part;

[0113] S200, for each measured depth of the underwater target, execute steps S210 to S260 respectively:

[0114] S210, adjusting the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod based on the measured depth;

[0115] S220, fixedly connecting the lower end of the second lower connecting rod to the center of mass of the underwater target, and adjusting the counterweight so that the underwater target is in a state of gravity and buoyancy balance in the experimental water pool;

[0116] S230, generating an internal solitary wave in the experimental water pool;

[0117] S240, respectively performing measurements in a vertical direction and a horizontal direction by the first measuring unit and the second measuring unit when the internal solitary wave passes through the underwater target;

[0118] S250, determining the vertical force exerted on the center of mass of the underwater target by the internal solitary wave based on the measurement result of the first measurement unit;

[0119] S260, determining the horizontal force exerted by the internal solitary wave on the center of mass of the underwater target based on the measurement result of the second measuring unit and the magnification, wherein the magnification is determined based on the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmission unit and the upper end of the upper connecting rod.

[0120] Obviously, in the process of adjusting the depth of the underwater target, the magnification may exceed a reasonable range (such as more than 12 times). Therefore, in some preferred embodiments, Fig. 20As shown, the measuring method also includes step S212 between steps S210 and S220: judging whether the magnification is within a preset magnification range according to the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmitting part and the upper end of the upper connecting rod; if not, adjusting the positions of the second measuring part and the force transmitting part until the magnification is within the preset magnification range.

[0121] In some specific embodiments, the amplification factor interval can be pre-set based on the amplitude of the internal solitary wave in the experimental water pool 7 collected in advance and the performance parameters of the selected force sensor to ensure that the force measurement results in two directions can be within a relatively ideal range within the amplification factor interval.

[0122] In addition, since the measurement system of the present application adopts a method of directly measuring the vertical force and amplifying the measurement of the horizontal force, the measurement error in the vertical direction is relatively consistent, and the measurement error in the horizontal direction will be coupled into the magnification factor, which is reflected as the difference between the ideal magnification factor and the actual magnification factor. At the same time, since the magnification factor needs to be controlled within a reasonable range, the vertical position of the force transmission part can be adjusted, resulting in the same ideal magnification factor may correspond to different DH values. Therefore, it is necessary to calibrate the measurement error in the vertical direction and the magnification factor in the horizontal direction in advance to ensure that after adjusting the depth of the underwater target 9 and / or adjusting the position of the force transmission part 3, the measurement error and the magnification factor can still be corrected more accurately.

[0123] Furthermore, since the measurement system provided in the present application directly measures and amplifies the vertical force and horizontal force at the lower end of the second lower link 12-2, respectively, the calibration device is configured to apply a standard reference force to the lower end of the second lower link 12-2 in the vertical and horizontal directions, respectively, to determine the measurement error of the first measuring part 1 in the measuring device 8 and the amplification factor of the second measuring part 2.

[0124] Fig.21 FIG. 4 shows a schematic diagram of the layout of the calibration device 5 included in the measurement system in some preferred embodiments. Fig. 22 right Fig.21 The middle circle C is enlarged and displayed, as shown in Fig.21 , Fig. 22As shown, the calibration device may include a plurality of standard weights 51 and a plurality of standard weights 52, wherein the standard weights 51 are placed in a tray 53 and directly hung on the end of the lower connecting rod 12 to apply a vertically downward standard reference force to the end; the standard weights 52 are also placed in the tray 53 and connected to the end of the lower connecting rod 12 through a pulley 54 to apply a horizontal standard reference force to the end. The installation position and installation method of the pulley 54 can be as follows: Fig.23 As shown, the supporting structure can be flexibly selected according to the actual support structure, and it only needs to ensure that the force generated by the standard weight 52 can be horizontally transmitted to the end of the lower connecting rod 12.

[0125] The first measuring part and the second measuring part are calibrated by the calibration device 5, specifically including obtaining the error correction value of the first measuring part and obtaining the magnification of the second measuring part. Obviously, the calibration step should be performed after the assembly of the measuring device is completed and before the lower end of the first measuring part is fixedly connected to the center of mass of the underwater target. Preferably, the calibration can be implemented by the following steps:

[0126] A plurality of groups of standard weights with different masses are sequentially hung at the lower end of the second lower connecting rod 12-2 to apply force thereto in the vertical direction, and an error correction value of the first measuring part 1 is determined based on each measurement result of the first measuring part 1, and the error correction value is used to correct the vertical force;

[0127] Several groups of standard weights with different masses that exert force on the second lower connecting rod 12 - 2 in the horizontal direction are hung in sequence at the lower end of the second lower connecting rod 12 - 2 , and the magnification factor is determined based on each measurement result of the second measuring part 2 .

[0128] Preferably, in the above-mentioned calibration step, standard weights 51 and 52 in two directions are placed in their respective trays 53 at the same time, that is, the standard reference force in the vertical direction for determining the error correction value of the first measuring part 1 and the standard reference force in the horizontal direction for determining the amplification factor are applied to the end of the second lower connecting rod 12-2 at the same time, so as to be more consistent with the actual state of the two measuring parts when measuring the internal solitary wave force.

[0129] Fig.24 , Fig.25 The measurement error of the vertical force and the magnification of the horizontal force obtained by hanging several standard weights are shown respectively. Fig.24 , Fig.25The difference between the two can be clearly distinguished: since the vertical force is measured directly, when the weight of the vertical force is changed, the measurement error in the vertical direction remains basically unchanged; the measurement error in the horizontal direction is coupled to the magnification, and due to the difference between the measured value and the true value of the magnification, as the weight of the horizontal force changes, the difference between the measured value and the true value of the amplified horizontal force gradually increases.

[0130] Obviously, the above calibration steps can be performed multiple times for different DH and DL values. For example, keeping DH unchanged, measuring the change of magnification with the change of DL, and fitting to obtain the curve of the change of magnification with the underwater target depth at a specific DH value, or keeping DH+DL unchanged, calibrating the curve of the change of magnification with the position of the force transmission part when the underwater target depth remains unchanged. By using the curve obtained by the above fitting, the appropriate magnification can be accurately selected when the position of the underwater target and the force transmission part is changed, so as to accurately correct the measurement results.

[0131] Fig.26 , Fig. 27 The vertical force and horizontal force of the internal solitary wave on the underwater target at different depths (upper layer of liquid, upper and lower layer interface, lower layer of liquid) are respectively shown using the depth-adjustable internal solitary wave force measurement system of the present application. Fig.26 , Fig. 27 It can be seen that, by using the technical solution of the present application, the internal solitary wave force at different depths can be accurately and conveniently measured.

[0132] 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. A depth-adjustable internal solitary wave force measurement system, comprising an experimental water pool, a wave-making mechanism, a wave-breaking mechanism, an underwater target and a measuring device, wherein the experimental water pool is filled with at least two liquids of different densities, the wave-making mechanism is used to create internal solitary waves in the experimental water pool, and the wave-breaking mechanism is used to eliminate the internal solitary waves, characterized in that: The measuring device comprises a first measuring part, a second measuring part, a force transmission part and a supporting structure arranged above the experimental water pool; The first measuring part comprises an upper connecting rod, a first dynamometer, a first lower connecting rod and a second lower connecting rod which are connected in sequence along a vertical direction, wherein the upper end of the upper connecting rod is rotatably connected to the supporting structure, and the direction of its rotation axis is perpendicular to the vertical direction and the propagation direction of the internal solitary wave at the same time, the lower end of the second lower connecting rod extends into the underwater target and is fixedly connected to the underwater target at its center of mass, and the distance from the lower end of the second lower connecting rod to the upper end of the upper connecting rod is adjustable; The second measuring part comprises a front connecting rod, a second dynamometer and a rear connecting rod which are sequentially connected along the propagation direction of the internal solitary wave, and the rear connecting rod is detachably fixedly connected to the supporting structure; The force transmission part includes a connecting part and a virtual connection part, wherein the connecting part is fixedly connected to the front connecting rod at one end facing the front connecting rod, and is fixedly connected to the virtual connection part at one end facing away from the front connecting rod, and the virtual connection part has a virtual connection channel running through the vertical direction, and one of the upper connecting rod, the first lower connecting rod, and the second lower connecting rod passes through the virtual connection channel and is virtually connected to the virtual connection part.

2. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: The second lower connecting rod is sleeved with the first lower connecting rod and can slide along the axial direction of the first lower connecting rod.

3. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: There are a plurality of second lower connecting rods with different lengths from each other, and the plurality of second lower connecting rods are selectively connected to the first lower connecting rod and the underwater target.

4. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: The distance from the rotation axis of the upper connecting rod to the mass center of the underwater target is 4 to 12 times the distance from the rotation axis of the upper connecting rod to the force transmission part.

5. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: The virtual connection portion is configured as a circular ring having a circular or elliptical cross section, or the virtual connection portion is configured as a rectangular ring having a wedge-shaped cross section.

6. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: The support structure includes a longitudinal support unit, a transverse support unit, a vertical support unit, an upper top plate arranged above the transverse support unit, and a side plate arranged on the side of the vertical support unit facing the propagation direction of the internal solitary wave. The lower surface of the upper top plate is provided with a hinged portion, the hinged portion includes a hinged seat, a rotating shaft and a bearing, the hinged seat is fixedly connected to the lower surface of the upper top plate, the rotating shaft is fixedly connected to the upper end of the upper connecting rod, and is rotatably connected to the hinged seat through the bearing; The side plate is provided with an adjustment and limiting mechanism, the rear connecting rod passes through the side plate, and the horizontal position of the rear connecting rod relative to the side plate is limited by the adjustment and limiting mechanism.

7. The depth-adjustable internal solitary wave force measurement system according to claim 6, characterized in that: The side plate is also provided with a sliding groove extending in the vertical direction and penetrating the side plate, so as to enable the second measuring part and the force transmitting part to slide in the vertical direction relative to the side plate.

8. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: It also includes an auxiliary positioning structure, which includes at least two auxiliary connecting rods with adjustable height in the vertical direction, and a ring fixedly connected to each auxiliary connecting rod, and the rings are respectively sleeved on the front and rear of the underwater target.

9. The depth-adjustable internal solitary wave force measurement system according to claim 1, characterized in that: It also includes a calibration device, which is configured to determine the measurement error of the first measuring part and the magnification of the second measuring part in the measuring device by applying a standard reference force to the lower end of the second lower connecting rod along the vertical direction and the horizontal direction respectively.

10. A method for measuring the internal solitary wave force, using the depth-adjustable internal solitary wave force measurement system of claim 1 to measure the internal solitary wave force exerted on an underwater target at different depths, characterized in that: The following steps are involved: S100, assembling the support structure, the first measuring part, the second measuring part, and the force transmission part, and adjusting the positions of the first measuring part, the second measuring part, and the force transmission part so that the force transmission part is in virtual contact with the first measuring part; S200, for each measured depth of the underwater target, execute steps S210 to S260 respectively: S210, adjusting the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod based on the measured depth; S220, fixedly connecting the lower end of the second lower connecting rod to the center of mass of the underwater target, and adjusting the counterweight so that the underwater target is in a state of gravity and buoyancy balance in the experimental water pool; S230, generating an internal solitary wave in the experimental water pool; S240, respectively performing measurements in a vertical direction and a horizontal direction by the first measuring unit and the second measuring unit when the internal solitary wave passes through the underwater target; S250, determining the vertical force exerted on the center of mass of the underwater target by the internal solitary wave based on the measurement result of the first measurement unit; S260, determining the horizontal force exerted by the internal solitary wave on the center of mass of the underwater target based on the measurement result of the second measuring unit and the magnification, wherein the magnification is determined based on the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmission unit and the upper end of the upper connecting rod.

11. The method for measuring internal solitary wave force according to claim 10, characterized in that: Also included between steps S210 and S220 is step S212: Whether the magnification is within a preset magnification range is determined based on the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmitting part and the upper end of the upper connecting rod. If not, the positions of the second measuring part and the force transmitting part are adjusted until the magnification is within the preset magnification range.

12. The method for measuring internal solitary wave force according to claim 11, characterized in that: A calibration step is also included before step S200, and the calibration step is used to determine the measurement error of the first measuring part, and the magnification is determined based on the distance between the lower end of the second lower connecting rod and the upper end of the upper connecting rod, and the distance between the force transmission part and the upper end of the upper connecting rod.

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