A method for measuring the force of internal solitary waves

Abstract

The application relates to an internal solitary wave acting force measuring method, which comprises the following steps: S1, measuring a first acting force F1' of an internal solitary wave on a first connecting rod by a first force gauge on the first connecting rod, the first connecting rod being fixedly connected with the center of mass of an underwater target along a Z-axis direction; S2, measuring a second acting force F2' of the internal solitary wave on a second connecting rod by a second force gauge on the second connecting rod, the second connecting rod being fixedly connected with the center of mass of the underwater target along a theta angle direction, and the theta angle direction being a direction with an angle of theta with the Z-axis in an XZ plane; and S3, determining an acting force Fx of the internal solitary wave on the center of mass of the underwater target along an X-axis direction based on the measurement results of the first acting force F1' and the second acting force F2', and the second acting force F2' balancing the component of the first acting force F1' in the direction of the second connecting rod. X , F1' and F X The second connecting rod balances the component of the first acting force F1' in the direction of the second connecting rod and the second acting force F2'. The application effectively reduces the problem of large error caused by too many connecting points of a complex multi-connecting rod force measuring structure, and does not need high-precision multi-component force sensors, and has the advantages of simple structure, low cost, more accurate measurement results and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of internal solitary wave experiment, and particularly relates to a depth-adjustable internal solitary wave force measurement method. BACKGROUND

[0002] Internal wave is a disturbance existing in stratified fluid in the ocean, and an internal solitary wave with a wavelength of 1-2 times the length of a submerged body is generally referred to as an internal solitary wave. As a special nonlinear internal wave, the internal solitary wave causes the submerged body to make large-amplitude up-and-down fluctuations with the internal solitary wave in the propagation process, which greatly affects the stability and controllability of the submerged body.

[0003] Internal solitary wave pool experiment is an important means to study the influence of internal solitary wave on the hydrodynamic performance of underwater submerged body. At present, quite a few schemes about internal solitary wave pool experiment have been disclosed. For example, patent 201810114516.7 discloses an experimental system for interaction between internal wave and submerged body, which measures the forces in three directions by using three pressure sensors arranged at the head, middle and side of the submerged body model. However, the measurement position of the above-mentioned method is the surface of the submerged body model, and the force condition at the center of mass cannot be directly obtained. In addition, due to the characteristics of internal solitary wave, the horizontal force and the vertical force may differ by one order of magnitude. In order to ensure the experimental accuracy, sensors with different ranges and accuracies are required, which increases the price and use cost of the experimental device. For another example, patent 202211064910.7 proposes an embedded force measurement method for the interaction between underwater structure and internal solitary wave, which embeds a force sensor into the underwater structure model to measure the three-dimensional force data of the structure model when the internal solitary wave passes. However, a multi-component force sensor that meets the requirements of one-tenth of the horizontal force and vertical force in terms of small force accuracy and range needs to be customized separately, and its price is much higher than that of a single-component force sensor. In addition, the sensor is built-in in the underwater submerged body model in the above-mentioned scheme. Since the fluid environment of the experiment usually contains oil and water, the installation and sealing of the sensor are greatly complicated, which undoubtedly increases the probability of damage to the sensor.

[0004] Therefore, the applicant has developed a multi-link structure, which can decompose the force of the underwater submerged body into horizontal and vertical components by using a multi-link structure. Two single-component force sensors can be used to measure the two components. However, in actual operation, too many linkages and too many connection points will cause new error problems. In addition, too much contact between parts will also affect the measurement of small forces.

[0005] Therefore, it is necessary to optimize the measurement system, minimize the number of linkages, and reduce the number of connection points to solve the problems existing in the above-mentioned various pool experiment schemes. SUMMARY

[0006] The purpose of the present application is to provide an internal solitary wave acting force measurement method to realize the force condition at the centroid of a submerged body model by measuring with lower cost and higher accuracy.

[0007] Embodiments of the present application can be implemented by the following technical solutions:

[0008] An internal solitary wave acting force measurement method comprises the following steps:

[0009] S1, measuring the first acting force of the internal solitary wave on the first connecting rod by the first force gauge mounted on the first connecting rod , wherein the first connecting rod is fixedly connected with the centroid of the underwater target along the Z-axis direction;

[0010] S2, measuring the second acting force of the internal solitary wave on the second connecting rod by the second force gauge mounted on the second connecting rod , wherein the second connecting rod is fixedly connected with the centroid of the underwater target along the direction , the direction is the direction with the included angle of with the Z-axis in the XZ plane;

[0011] S3, determining the acting force of the internal solitary wave on the centroid of the underwater target along the X-axis direction based on the measurement results of the first acting force and the second acting force , wherein , and are balanced.

[0012] Further, the upper limit of the angle is determined based on the measurement result of the first acting force , the first lever arm of the second force gauge , and the anti-torque limit of the second force gauge ;

[0013] or based on the maximum acting force of the internal solitary wave along the Z-axis direction , the second lever arm of the second force gauge , and the anti-torque limit of the second force gauge .

[0014] Further, the upper limit of the angle is obtained according to the following formula,

[0015] ,

[0016] wherein is the measurement result of the first force gauge,​ an empirical value of the maximum force exerted by the internal solitary wave along the X-axis direction, a distance from the second force gauge to the center of mass of the underwater target, a torque resistance limit of the second force gauge.

[0017] Further, the the upper limit of the angle is obtained according to the following formula,

[0018] ,

[0019] wherein, an empirical value of the maximum force exerted by the internal solitary wave along the Z-axis direction, an empirical value of the maximum force exerted by the internal solitary wave along the X-axis direction, a distance from the second force gauge to the inflection point A along the direction of the second connecting rod, a torque resistance limit of the second force gauge.

[0020] Further, between step S1 and step S2, there is also step S12:

[0021] Based on the upper limit of the angle, the angle between the second connecting rod and the Z-axis in the XZ plane is adjusted.

[0022] Further, when the angle between the second connecting rod and the Z-axis in the XZ plane is determined, the installation position of the second force gauge relative to the second connecting rod can be set by calculating the limit value of the force arm determined according to the following formula,

[0023] ,

[0024] wherein, a measurement result of the first force gauge, an empirical value of the maximum force exerted by the internal solitary wave along the X-axis direction, a torque resistance limit of the second force gauge.

[0025] Further, the first force gauge and / or the second force gauge are arranged at a position close to the center of mass of the underwater target and above the liquid surface of the experimental pool.

[0026] Further, force balance decomposition is made along the direction of the second connecting rod, and the force of the internal solitary wave along the X-axis direction is obtained according to the following formula, ,

[0027] ,​​

[0028] wherein, is the internal solitary wave force acting on the first force gauge along the Z-axis direction, , is the internal solitary wave force acting on the second force gauge along the direction of the second connecting rod, .

[0029] Further, the internal solitary waves applied in step S1 and step S2 are of the same characteristics.

[0030] Further, the acting forces measured in step S1 and step S2 are measured when the underwater target is in a state of balance between gravity and buoyancy in the experimental pool.

[0031] Further, the first connecting rod and the second connecting rod are of a split structure, or the first connecting rod and the second connecting rod are fixedly connected as an integral structure.

[0032] Further, when the first connecting rod and the second connecting rod are of an integral structure, a measuring device is used to measure the internal solitary wave, the measuring device comprising the first connecting rod, the second connecting rod, an acting force transmission part, a support structure, and a limiting structure, the support structure being arranged above the experimental pool, the acting force transmission part being a hinged structure, and the adjusting limiting mechanism being slidably connected to a support unit of the support structure;

[0033] The adjusting limiting mechanism comprises a first limiting block and a second limiting block, the first limiting block being fixedly connected to the support structure, and the second limiting block being rotatably connected to one side of the first limiting block along the Y-axis direction, the rotation direction being parallel to the XZ plane.

[0034] The first connecting rod comprises a first upper connecting rod and a first lower connecting rod fixedly connected at both ends of the first force gauge along the Z-axis direction, the other end of the first lower connecting rod being fixedly connected to the center of mass of the underwater target, and the other end of the first upper connecting rod being connected to a first connecting part of the acting force transmission part.

[0035] The second connecting rod comprises a second upper connecting rod and a second lower connecting rod fixedly connected at both ends of the second force gauge along the angle direction, wherein the second upper connecting rod is connected to the support structure through the first limiting block, and the second lower connecting rod is fixedly connected to the first upper connecting rod through the acting force transmission part.

[0036] Further, between step S12 and step S2, there is also included,

[0037] Based on the position of the underwater target in S1, the length of the second connecting rod in the XZ plane is adjusted so that the depth information and the position information of the underwater target in the experimental pool remain unchanged.

[0038] Furthermore, when the first link and the second link are an integral structure, a measuring device is used to measure the internal solitary wave. The measuring device includes the first link, the second link, a force transmission part, and a support structure, and the support structure is disposed above the experimental water tank.

[0039] The force transmission part includes an integral connector consisting of a first connecting part, a corner part, and a second connecting part;

[0040] The first connecting rod includes a first upper connecting rod and a first lower connecting rod fixedly connected to both ends of the first force gauge along the Z-axis direction. The other end of the first lower connecting rod is fixedly connected to the center of mass of the underwater target, and the other end of the first upper connecting rod is connected to the first connecting part of the force transmission part.

[0041] The second link includes a second upper link, one end of which is along... One end is connected to the support structure at an angle, and the other end is connected to one end of the second force gauge. The other end of the second force gauge is connected to the second connecting part of the force transmission part.

[0042] The embodiment of this application provides a method for measuring the force of an internal solitary wave, which has at least the following beneficial effects:

[0043] This application only requires two connecting rods, and a single force sensor is set on each of the two connecting rods. By simply decomposing the force, the force at the center of mass of the underwater submersible can be measured. It does not require a complex multi-link structure, effectively avoiding the problem of large errors caused by too many connection points. Moreover, it does not require high-precision multi-force sensors, and has the advantages of simple structure, lower cost, and more accurate measurement results.

[0044] In addition, the measurement of internal solitary waves at different depths can be achieved by adjusting the upper connecting rod and using a horizontally movable support, without needing to increase or decrease the number of devices, making it simple and easy to implement.

[0045] Building upon this, by upgrading the first and second connecting rods into a single integrated structure, where two force gauges are simultaneously mounted on the connecting rods for measurement, not only can integrated measurement be achieved, but also... By setting the angle range, the influence of torque on measurement accuracy is avoided, making this solution lower in cost and simpler to measure compared to existing solutions, while ensuring measurement accuracy. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of a sensor setup for testing the force of internal solitary waves acting on an underwater target.

[0047] Figure 2 This is a schematic diagram of the layout of a measurement system for measuring internal solitary waves according to a method for measuring the force of internal solitary waves in accordance with this application;

[0048] Figure 3 A flow chart of a method for measuring the force of internal solitary wave according to an embodiment of the present application;

[0049] Figures 4 to 7 A schematic diagram of a force analysis principle according to an embodiment of the present application;

[0050] Figure 8 A specific structural schematic diagram of a device for measuring the force of internal solitary wave according to some embodiments of the present application is shown;

[0051] Figure 9 A sectional view of a force transmission part according to an embodiment of the present application;

[0052] Figure 10 A sectional view of a force transmission part according to an embodiment of the present application;

[0053] Figure 11 A schematic diagram of an adjusting limiting mechanism according to an embodiment of the present application.

[0054] Reference numerals in the drawings

[0055] 11 - first load cell; 12 - first lower connecting rod; 13 - first upper connecting rod;

[0056] 21 - second load cell; 22 - second lower connecting rod; 23 - second upper connecting rod;

[0057] 3 - force transmission part; 31 - first connecting part; 32 - corner part; 33 - second connecting part;

[0058] 4 - support structure;

[0059] 5 - adjusting limiting mechanism; 51 - first limiting block; 52 - second limiting block; 521 - through hole; 522 - fastening structure;

[0060] 7 - experimental water pool; 71 - water pool wall; 72 - water pool horizontal support; 73 - water pool vertical support;

[0061] 8 - measuring device;

[0062] 9 - underwater target; 91 - center of mass 91; 901 - first measuring point; 902 - second measuring point; 903 - third measuring point. DETAILED DESCRIPTION

[0063] Hereinafter, the present application is further described based on preferred embodiments and with reference to the accompanying drawings.

[0064] In addition, various components on the drawings are enlarged (thick) or reduced (thin) for the convenience of understanding, but such practice is not intended to limit the protection scope of the present application.

[0065] Singular forms of words also include plural meanings, and vice versa.

[0066] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, in the description of this application, in order to distinguish different units, the terms "first," "second," etc. are used in this specification, but these are not limited by the manufacturing order, nor should they be construed as indicating or implying relative importance. Their names may differ in the detailed description and claims of this application.

[0067] The vocabulary used in this specification is for illustrative purposes and is not intended to limit the scope of this application. It should also be noted that, unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection via an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of these terms in this application.

[0068] To explain the technical solution of this application in detail, we will first introduce the method of measuring the force of internal solitary waves on underwater targets in existing water tank experiments.

[0069] Figure 1 This paper illustrates a scheme for measuring the internal solitary wave force by deploying multiple force sensors on the surface of an underwater target 9. The underwater target 9 can be a scaled-down model of a real underwater submersible, such as... Figure 1 As shown, pressure sensors are deployed at a first measuring point 901 directly in front of the underwater target 9, a second measuring point 902 to the side, and a third measuring point 903 directly above it to obtain the components of the internal solitary wave force acting on the underwater target 9 in various directions. However, this measurement scheme has the following problems that need to be overcome in the actual force measurement process:

[0070] 1) Since the sensors are deployed at various points on the outer surface of the underwater target 9, the measured results are not the force exerted on the center of mass 91 (obviously, it is impossible to place more than one sensor at the center of mass 91). At the same time, since the shape of the underwater target 9 is irregular, it is necessary to perform cumbersome calibration or add additional attitude measurement devices such as gyroscopes to ensure that the force directions of each sensor are orthogonal to each other, which undoubtedly increases the complexity of experimental operation and data processing.

[0071] 2) Due to the characteristics of internal solitary waves, the vertical force at their point of action often exceeds the horizontal force along the propagation direction by an order of magnitude. Simultaneously, the horizontal force along the propagation direction is significantly greater than the force in another horizontal direction perpendicular to it. Figure 1 With the setup shown, the force components of the internal solitary wave measured at the three measurement points exhibit the following relationship:

[0072] ,

[0073] Obviously, if a single-component force sensor of the same specification is selected, and it meets the resolution requirements to be able to handle smaller forces, such as... or When measuring accurately, then It may have exceeded its measurement range; conversely, if the safety of the measurement range is prioritized, it may not be possible to accurately measure the minute components of the force.

[0074] 3) This scheme places multiple sensors directly in liquids such as oil and water, which not only greatly increases the probability of sensor damage, but also makes it difficult to flexibly adjust the depth of underwater targets.

[0075] Apart from Figure 1 In addition to the scheme shown, there is also a technical scheme that directly places the multi-component force sensor inside the underwater target 9, such as at the center of mass 91, so as to directly collect the three orthogonal components of the internal solitary wave force at that location. Generally, this scheme requires the use of a high-precision measuring instrument: a six-component force sensor, which can simultaneously measure the force and torque of an object on three mutually perpendicular principal axes, hence the name six-component force sensor.

[0076] The measurement principle of the six-component force sensor is based on the bridge balance of strain gauges. The size of force and torque is calculated by measuring the resistance change of the strain gauges. In the six-component force sensor, three mutually perpendicular strain gauges are usually used as the bridge arms of the bridge. Two strain gauges are used to measure the force and torque in the X and Y 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 measurement platform of the six-component force sensor, the strain gauges will deform due to the action of force and torque, causing the resistance to change. By measuring the change of resistance, the size of the force and torque acting on the object can be calculated.

[0077] There are many factors that affect the accuracy of the six-component force sensor. The most important reason is the inter-channel coupling. In physics, it refers to the phenomenon that two or more systems or two forms of motion influence each other through interaction and combine together. The input signal in each of the six channels of 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 signals collected by the multi-component force sensor must be decoupled to eliminate the coupling effect between the signals in different directions.

[0078] Generally, decoupling or suppressing coupling can be done in two ways. The first is done before the sensor is produced, which is generally called structural decoupling, that is, to eliminate or suppress coupling from the design of the sensor. This method involves the manufacturing process of the sensor, which is often difficult and may increase the cost. The second is to use a systematic mathematical model for matrix operation decoupling.

[0079] However, as analyzed above, due to the difference in the size of the three orthogonal components of the internal solitary wave by an order of magnitude, the multi-component force sensor needs to realize high-precision measurement in a range of orders of magnitude, therefore, if structural decoupling is used, the multi-component force sensor needs to be customized separately according to the range and accuracy of each direction; if mathematical matrix operation decoupling is used, the cross-order difference of the signals in each direction will greatly affect the accuracy of the matrix operation, and even lead to the failure to obtain a stable solution.

[0080] In addition, due to the need to place the expensive multi-component force sensor below the liquid surface of the water, oil and other mixed liquids, in order to reduce the probability of damage to the multi-component force sensor, it is obvious that the water-tight structure of the underwater target 9 is required to be higher.

[0081] It can be seen that how to realize accurate, low-cost and convenient measurement of the internal solitary wave force in the pool experiment environment is a problem to be solved. Therefore, the embodiment of the present application provides an internal solitary wave force measurement method different from the foregoing.

[0082] Figure 2 This diagram illustrates the setup of a measurement system for measuring internal solitary waves according to a method for measuring the force of internal solitary waves based on this application. Figure 2 As shown, the measurement system includes an experimental water tank 7, a measuring device 8, an underwater target 9 (shown as a dashed line in the figure), and wave-generating and wave-damping mechanisms not shown in the figure.

[0083] The experimental water tank 7 can be constructed in a manner known to those skilled in the art. For example, the frame structure of the water tank can be constructed by multiple horizontal supports 72 and vertical supports 73. Various watertight materials are used as the walls 71 and bottom of the water tank within the frame structure, thereby obtaining the experimental water tank 7.

[0084] Experimental water tank 7 generally adopts, for example Figure 2 The elongated structure extending along the X-axis shown has a wave-generating mechanism at one end. This mechanism generates an internal isolated wave that propagates unidirectionally along the X-axis at the interface between two liquids. When the internal isolated wave passes the underwater target 9, the force exerted by the internal isolated wave on the underwater target 9, which is below the liquid level in the experimental water tank 7, can be measured by the measuring device 8. The other end of the experimental water tank 7 is equipped with a wave-damping mechanism to prevent the internal isolated wave from propagating in the reverse direction within the experimental water tank.

[0085] In the embodiments of this application, the X-axis direction represents the horizontal propagation direction of the inner solitary wave, and the Z-axis direction is the vertical direction. The force exerted by the inner solitary wave along the Z-axis is assumed to be... The force applied along the X-axis is The Y-axis is the opposite direction to the X-axis, and obviously the X, Y, and Z axes are orthogonal to each other.

[0086] Based on the above measurement system, this application provides a method for measuring the force of an internal solitary wave, such as... Figure 3 As shown, it includes the following steps:

[0087] S1, the first force exerted on it by the internal solitary wave is measured by the first force gauge mounted on the first connecting rod. The first connecting rod is fixedly connected to the center of mass of the underwater target 9 along the Z-axis.

[0088] S2, the second force exerted on it by the internal solitary wave is measured by the second force gauge mounted on the second connecting rod. Among them, the second link along The angular direction is fixedly connected to the center of mass of the underwater target 9. The angular direction is the angle between the XZ plane and the Z-axis. The direction;

[0089] S3, based on the first force and the second force The measurement results determined the force exerted on the center of mass of underwater target 9 by the internal solitary wave along the X-axis. ,in, and The component in the direction of the second link and the second force balance.

[0090] In some preferred embodiments, the first connecting rod and the second connecting rod are separate structures, or the first connecting rod and the second connecting rod are fixedly connected as an integral structure. When the first connecting rod and the second connecting rod are fixedly connected to the underwater target 9 respectively, two measurements are required to obtain the measurement result. When the first connecting rod and the second connecting rod are fixedly connected as an integral structure, only one measurement is required to obtain the measurement result.

[0091] Specifically, such as Figures 4 to 6 As shown, when the first connecting rod and the second connecting rod are fixedly connected to the underwater target 9, the measurement steps are as follows:

[0092] S100, the first force gauge 11 is assembled on the first connecting rod, and one end of the first connecting rod is fixedly connected to the center of mass of the underwater target 9, and the other end is fixedly connected to the support structure 4;

[0093] S200, generating an internal solitary wave in the experimental water tank;

[0094] S300, the first force exerted on the underwater target 9 by the internal solitary wave in the Z-axis direction by the first force gauge 11 is measured. ;

[0095] S400, the second force gauge 21 is mounted on the second connecting rod, and the first connecting rod is replaced with the second connecting rod, wherein the second connecting rod has an angle with the Z-axis in the XZ plane. One end of the second connecting rod is fixedly connected to the center of mass of the underwater target 9, and the other end is fixedly connected to the support structure 4;

[0096] S500, generates an internal solitary wave in the experimental water tank;

[0097] S600, the second force gauge 21 measures the force exerted on the underwater target 9 by the internal solitary wave as it passes through it. ;

[0098] S700, based on first action force and the second force The measurement results determine the force exerted on the center of mass of the underwater target 9 by the internal isolated wave in the X-axis direction, wherein, and The component in the direction of the second link and the second force balance.

[0099] Clearly, the above operation only requires two separate measurements; the first measurement should be of the initial force applied to the first link. Let's first measure the second force of the second link. There is no order requirement.

[0100] In some preferred embodiments, the internal isolated waves generated in steps S200 and S500 have the same characteristics, that is, the internal isolated waves generated in the two steps have the same amplitude, period and velocity.

[0101] In some preferred embodiments, the first force gauge 11 and the second force gauge 21 are single-component S-type sensors, whose working principle mainly relies on the deformation of an elastic body (or sensitive beam) under external force. When an external force acts on the elastic body of the sensor, the elastic body undergoes elastic deformation, causing the resistance strain gauge attached to the surface of the elastic body to deform accordingly. This deformation causes a change in the resistance of the resistance strain gauge (increase or decrease), and then this resistance change is converted into an electrical signal (usually voltage or current) through a corresponding measurement circuit, thus completing the process of converting the external force into a measurable electrical signal. When the S-type sensor measures force in the measurement direction, if it is also subjected to forces and torques in other directions, it will have a certain impact on the safety and accuracy of the sensor. To ensure its normal and safe operation and accurate accuracy, it needs to be operated within the sensor's extreme force limits.

[0102] When the internal solitary wave propagates head-on to the underwater target 9, such as Figure 4 As shown, the underwater target 9 is mainly subjected to the horizontal component of force. Vertical component force The combined effect of the two forces, let the horizontal component of the internal solitary wave be... The force transmitted to the first force gauge 11 is the first horizontal component. The vertical component of the internal isolated wave The force transmitted to the first force gauge 11 is the first vertical component. In the first horizontal component force First vertical component Under the action of the first force gauge 11 on the first connecting rod, a first torque will be generated. The first torque This will affect the measurement accuracy of the first force gauge 11. However, due to the characteristics of internal solitary waves, the vertical force at its point of action often exceeds the horizontal force along the propagation direction by an order of magnitude, resulting in the horizontal component of the internal solitary wave... The first horizontal component is very small, therefore, This can be ignored, which means that the first torque generated by the internal solitary wave on the first force gauge 11 is negligible. The torque is very small and does not exceed the torque resistance limit of the first force gauge 11, which ensures that the measurement result of the first force gauge 11 is very accurate.

[0103] Based on this, when the horizontal force of the internal isolated wave is transmitted to the underwater target 9, since the two ends of the first connecting rod are fixedly connected to the center of mass of the underwater target 9 and the support structure 4 respectively, and the first force gauge 11 is set along the Z-axis, the vertical component of the internal isolated wave... The force is directly transmitted as the first vertical component of the first force gauge 11. At this time, the first measurement result displayed by the first force gauge 11 The first vertical component of the force of the first force gauge 11 This is also the vertical force of the internal isolated wave. .

[0104] Of course, the measurement result of the first force gauge 11 is also related to the distance between the first force gauge 11 and the center of mass of the underwater target 9. The closer the first force gauge 11 is to the center of mass of the underwater target 9, the more accurate the measurement result of the first force gauge 11. However, if the first force gauge 11 is installed at the center of mass of the underwater target 9, the first force gauge 11 needs to be watertight. Obviously, this places higher demands on the watertight structure of the underwater target 9. Therefore, we can choose to set the first force gauge 11 at a position close to the center of mass of the underwater target 9 and above the liquid surface of the experimental pool.

[0105] As for the angle between the second connecting rod and the center of mass of the underwater target 9 This setting is also to make the measurement results of the second force gauge 21 more accurate. The upper limit of the angle is based on the first force. The measurement results, the first lever arm of the second force gauge and the torque resistance limit of the second force gauge Sure.

[0106] Specifically, in theory, such as Figure 5 As shown, if the second connecting rod is connected to the center of mass of the underwater target 9 along the X-axis (i.e., When the underwater target 9 is in a state of equilibrium between gravity and buoyancy in the experimental pool and there is no torque, the result measured by the second force gauge 21 is the horizontal force exerted on the underwater target 9 in the X-axis direction by the inner solitary wave when it passes through the underwater target 9. However, due to the characteristics of the inner solitary wave, a vertical force is transmitted at its point of action. This causes the second connecting rod to generate torque under the action of the vertical and lateral forces of the inner solitary wave. The second torque of the inner solitary wave on the underwater target 9 is... The following formula can be used to derive:

[0107] ,

[0108] At this time, the first lever arm The distance from the second force gauge 21 to the center of mass of the underwater target 9 is given by... The measurement results from the first measuring instrument can be used. Reading, thus, the torque resistance limit of the second force gauge 21 It can be derived from the following formula:

[0109] ,

[0110] in, The measurement result of the first force gauge. The distance from the second force gauge to the center of mass of the underwater target is [distance missing]. This is an empirical value representing the maximum force exerted on the internal isolated wave along the X-axis. This is the torque resistance limit of the second force gauge.

[0111] In order to reduce the second torque The impact on the measurement accuracy of the second measuring instrument, besides reducing the first lever arm, is... The length can also be adjusted according to the torque resistance limit of the second force gauge 21, by reducing its size. In the way of angle, Set it within its reasonable range to improve measurement accuracy.

[0112] For example, for an S-type sensor with a 10N range, its torque resistance limit... It cannot exceed 0.25 Nm. The calculation uses the following formula:

[0113] ,

[0114] According to the numerical simulation results, when the first lever arm When the length is 0.2m, according to the measurement results of the first force gauge The measurement results of the first force gauge It is 5N. When the value is 0.3N, substituting the values ​​yields the angle. The maximum value is calculated. The maximum value is no more than 16°.

[0115] In some preferred embodiments, since the first link and the second link are two independent links, the angle between the second link and the Z-axis in the XZ plane can be adjusted based on the first measurement result. Step S12 is also included between steps S1 and S2: based on... The upper limit of the angle is adjusted by setting the angle between the second link and the Z-axis in the XZ plane, so that the angle between the second link and the Z-axis in the XZ plane is set within a reasonable range, thereby improving the measurement accuracy.

[0116] In some preferred embodiments, when a reasonable range is selected When calculating the value of an angle, such as... Figure 6 As shown, due to The angle is selected within a reasonable range based on the torque resistance limit of the second force gauge 21; therefore, the generated second torque force... This will not affect the measurement result of the second force gauge 21. At this time, the second force gauge 21 displays the second force. This is the second vertical force. ,in, and The component in the direction of the second link and Balance can be achieved by The following formula is derived:

[0117] ,

[0118] Among them, it is known , , , The readings can be obtained using the corresponding force gauges, and Since the angle is known, it can be directly calculated. .

[0119] Obviously, the second link in the XZ plane and its relationship with the Z-axis... Given a fixed angle, the lever arm can also be reduced. To improve measurement accuracy, the distance between the second force gauge 21 and the center of mass of the underwater target 9 is adjusted, and the lever arm... Based on the torque resistance limit of the second force gauge The reasonable range is determined based on the numerical simulation results using the following formula.

[0120] ,

[0121] in, The measurement results of the first force gauge 11 This is the torque resistance limit of the second force gauge 21. The empirical value for the maximum force exerted on the internal isolated wave along the X-axis direction is given by the following: Given the angle, find Based on the obtained lever arm The value is adjusted to determine the distance between the second force gauge 21 and the center of mass of the underwater target 9.

[0122] In some preferred embodiments, when the first link and the second link are fixedly connected as a single unit, and the measurement result can be obtained with only one operation, the measurement steps are as follows:

[0123] S100, the first force gauge 11 is assembled into the first connecting rod, and the second force gauge 21 is assembled into the second connecting rod. The ends of the first connecting rod and the second connecting rod have an included angle in the XZ plane. The first connecting rod is fixedly connected to the center of mass of the underwater target 9 along the Z-axis, and the other end of the second connecting rod is fixedly connected to the support structure 4.

[0124] S200, generating an internal solitary wave in the experimental water tank;

[0125] S300, read the measurement results of the first force gauge 11 respectively, the first force. The measurement result of the second force gauge 21 is the second force. ;

[0126] S400, based on the first force and the second force The measurement results determine the X-axis force exerted on the center of mass of the underwater target 9 by the internal isolated wave, wherein, and The component in the direction of the second link and balance.

[0127] In some preferred embodiments, the first force gauge 11 and the second force gauge 21 are single-component S-type sensors.

[0128] Of course, since the first link and the second link are fixedly connected, the angle between the second link and the first link in the XZ plane is... It needs to be set up before measurement, the aforementioned The upper limit of the angle is based on the maximum force exerted by the internal isolated wave along the Z-axis. The second lever arm of the second force gauge and the torque resistance limit of the second force gauge Sure.

[0129] Specifically, the force on the second force gauge 21 can be decomposed into forces along... The second vertical force in the angular direction and perpendicular to Second horizontal force in the angular direction Among them, the horizontal component of the internal solitary wave Vertical component of internal solitary wave and the second lever arm This causes the second force gauge 21 to be subjected to a second torque. At this time, the The upper limit of the angle is determined by the following formula:

[0130] ,

[0131] in, This is an empirical value representing the maximum force exerted on the internal isolated wave along the Z-axis. The second lever arm is the empirical value of the maximum force exerted on the internal isolated wave along the X-axis direction. The distance from the second force gauge 21 to the inflection point A where the first and second connecting rods intersect is... This is the torque resistance limit of the second force gauge 21.

[0132] Obviously, the second link in the XZ plane and its relationship with the Z-axis... Given a fixed angle, the lever arm can also be reduced. This method improves measurement accuracy.

[0133] It should be added that, because Angle is a quantity that only has a maximum value, not a minimum value. The minimum value is infinitely close to 0. Usually, it is set as close to the maximum value as possible. Second lever arm This means setting it to the minimum possible value. Generally, it's based on the second lever arm. To determine the angle, the second lever arm The selection of the test conditions takes into account factors such as the changes in test conditions and the strength of the connection points.

[0134] In some specific embodiments, the maximum horizontal force of the internal solitary wave provided by the experimental water tank 7 is determined based on experience. and maximum vertical force When the torques are 0.8N and 10N respectively, the torque measurement limit of the selected force gauge is 0.25Nm. When the value is 0.03m, the The angle ranges from 0.5° to 51.5°, when the second lever arm... When the value is 0.2m, the The angle ranges from 0.5° to 2.5°, due to the second lever arm. The selection of the second lever arm takes into account factors such as changes in test conditions and the strength of the connection points. To determine the angle, it is necessary to satisfy the second torque generated by different internal solitary waves on the second force gauge during the measurement process. None of them exceed their torque resistance limit This ensures the accuracy of the measurement results.

[0135] In some preferred embodiments, when selected within a reasonable range When calculating the value of an angle, such as... Figure 7 As shown, due to The angle is selected within a reasonable range based on the bending moment resistance limit value of the second force gauge 21. Therefore, the generated second torque force This will not affect the accuracy of the measurement result of the second force gauge 21. At this time, the second force gauge 21 displays the second force. This is the second vertical force. By performing force equilibrium decomposition along the direction of the second link, it can be determined by... The following formula is derived:

[0136] ,

[0137] Among them, it is known , , , The readings can be obtained using the corresponding force gauges, and Since the angle is known, it can be directly calculated. .

[0138] In some preferred embodiments, due to the distance from the second force gauge 21 to the inflection point A, the... The value of the angle will affect the accuracy of the measurement results. Therefore, the applicant has optimized the structure of the first link and the second link.

[0139] Specifically, Figure 8 A schematic diagram of the specific structure of the internal solitary wave force measuring device 8 provided according to some embodiments of this application is shown, such as... Figure 8 As shown, the measuring device 8 includes a first connecting rod, a second connecting rod, a force transmission part 3, and a support structure 4. The support structure 4 is located above the experimental water tank 7 and is used to position and support the measuring device 8.

[0140] Specifically, the first connecting rod includes a first upper connecting rod 13 and a first lower connecting rod 12, which are fixedly connected to the two ends of the first force gauge 11 along the Z-axis direction, respectively. The other end of the first lower connecting rod 12 is fixedly connected to the center of mass 91 of the underwater target 9, and the other end of the first upper connecting rod 13 is connected to the force transmission part 3.

[0141] The second link includes along The second upper connecting rod 23 and the second lower connecting rod 22 are fixedly connected to the two ends of the second force gauge 21 in terms of angle direction, wherein the second upper connecting rod 23 is connected to the support structure 4.

[0142] Furthermore, the first and second links are rigidly connected by a force transmission part 3, which enables the force exerted on the center of mass 91 of the underwater target 9 to be entirely transmitted to the second link via the first link, without being affected by other forces at the connection point; specifically, Figure 9 The specific structure of the force transmission part 3 in some embodiments of this application is shown. It includes an integral connector composed of a first connecting part 31, a corner part 32, and a second connecting part 33. The first connecting part 31 and the second connecting part 33 are respectively provided with a first fixing groove and a second fixing groove that cooperate with the first upper connecting rod 13 and the second lower connecting rod 22. The ends of the first upper connecting rod 13 and the second lower connecting rod 22 are respectively inserted into the fixing grooves at both ends to achieve a fixed connection. The corner part 32 has a corner that deviates along the Z-axis direction to achieve the deflection of the second lower connecting rod 22 relative to the first upper connecting rod 13. Angular connection; specifically, the connection between the fixing groove and the rod can be achieved by threaded connection or interference fit.

[0143] In some preferred embodiments, to achieve even more accurate measurements, such as Figure 10 As shown, it can also be configured such that one end of the force transmission part 3 is connected to the first connecting rod, and the other end is connected to the second force gauge 21, that is, one end of the second upper connecting rod 23 is along... The angle direction is connected to the support structure 4, and the other end is connected to one end of the second force gauge 21. The other end of the second force gauge is connected to the second connecting part 33 of the force transmission part 3, which is used to reduce the second lever arm. .

[0144] In some other embodiments, the force transmission part 3 can also be a conventional rigid connection method in the art, such as screw connection, welding, etc., as long as it can achieve a rigid connection of two rods at a certain angle.

[0145] In some preferred embodiments, the force transmission part 3 is specifically a hinged structure, which allows for adjustment of the appropriate force transmission part according to changes in experimental conditions such as the amplitude of the internal solitary wave and the measurement position during the experiment. The angle is adjusted to achieve more accurate measurement; specifically, the hinge structure includes through holes respectively provided at the ends of the first upper connecting rod 13 and the second lower connecting rod 22, and bolts that cooperate with them.

[0146] In addition, in order to measure the force of internal isolated waves at different locations in the experimental water tank 7 and to better study the characteristics of internal isolated waves, the applicant has made further improvements to the above-mentioned measuring device 8.

[0147] In some preferred embodiments, the support structure 4 is movably connected to the experimental water tank 7, allowing the measuring device 8 to slide along the experimental water tank 7 in the X-axis direction. Alternatively, the upper top plate of the support structure 4 can be movably connected to other support units, allowing the measuring device 8 to slide relative to the experimental water tank 7 in the Y-axis direction, facilitating adjustment of the force-measuring position of the measuring device 8.

[0148] In some preferred embodiments, the second upper connecting rod 23 is connected to the support structure 4 via an adjusting limiting mechanism 5, such as... Figure 11 As shown, the adjusting limit mechanism 5 is detachably connected to the second upper connecting rod 23 for limiting its position. The second upper connecting rod 23 is provided with scale lines. In use, different measurement positions can be achieved by adjusting the limiting positions of the second upper connecting rod 23 and the adjusting limit mechanism 5.

[0149] In some embodiments of this application, the adjusting limiting mechanism 5 includes a first limiting block 51 and a second limiting block 52, which are rotatably connected. The first limiting block 51 is fixedly connected to the support structure 4, and the second limiting block 52 is rotatably connected to one side of the first limiting block 51 along the Y-axis, with its rotation direction parallel to the XZ plane. Further, the second limiting block 52 is provided with a through hole 521 that matches the second upper connecting rod 23, and a fastening structure 522. Specifically, the fastening structure 522 is a set screw type. The positioning of the second connecting rod and its rotation in the XZ plane can be realized by adjusting the limiting mechanism 5.

[0150] Furthermore, the adjusting and limiting mechanism 5 is slidably connected to the support unit of the support structure 4. Specifically, the slidable connection can be achieved by setting a sliding groove slider structure. Preferably, the sliding direction is parallel to the X-axis direction.

[0151] In some preferred embodiments, the first lower connecting rod 12 is a length-adjustable connecting rod, and the measurement depth of the underwater target 9 can be quickly changed by adjusting the length of the first lower connecting rod 12. In some specific embodiments, the length-adjustable connecting rod can be composed of two interlocking rods, that is, one rod is set as a hollow cylindrical tube so that it can be sleeved on the outside of the other, and the two have a stud structure and a screw hole structure that cooperate with each other, and the degree of extension and retraction between the two can be adjusted by rotation; in some other embodiments, the length-adjustable connecting rod is composed of two interlocking rods, one of which is provided with multiple through holes arranged axially at intervals, and the other rod is provided with a ball that can be pressed and bounced up after the pressing is released. When the two rods move axially relative to each other, the ball bounces up after entering a certain through hole, limiting the position of the two rods, thereby realizing the length adjustment.

[0152] Furthermore, the second upper connecting rod 23 is an adjustable length connecting rod, which works in conjunction with the force transmission part 3 and the adjustment and limiting mechanism 5 to achieve different... The angle is adjusted to ensure that the underwater target 9 remains at a constant depth and position in the experimental pool 7 at different angles. The specific structure of the length-adjustable connecting rod is similar to that of the first lower connecting rod 12, and will not be described in detail here.

[0153] Accordingly, between steps S12 and S2, the length of the second connecting rod in the XZ plane is adjusted based on the location of the underwater target in S1, so that the depth information and position of the underwater target in the experimental pool remain unchanged, in order to avoid errors caused by different measurement depths to the results.

[0154] Obviously, by optimizing the structure of the measuring device 8, when it is necessary to measure the internal solitary wave force after the water depth information has been changed, it is only necessary to adjust the length of the second link and adjust the connection position between the adjustment limit mechanism 5 and the support structure 4.

[0155] In some preferred embodiments, a counterweight is also provided inside the underwater target 9. The appropriate counterweight can be set according to the weight and buoyancy of the underwater target 9 so that the underwater target 9 does not exert any force on each force gauge when the internal solitary wave does not arrive.

[0156] The specific embodiments of this application have been described in detail above. For those skilled in the art, several improvements and modifications can be made to this application without departing from the principle of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A method of measuring the force of an internal solitary wave, characterized by, The method comprises the following steps: S1, measuring a first action force exerted by the internal solitary wave on the first force gauge mounted on the first connecting rod wherein the first connecting rod is fixedly connected with the center of mass of the underwater target in the direction of the Z axis. S2, measuring a second action force exerted by the internal solitary wave on the second connecting rod through a second force gauge mounted on the second connecting rod , wherein the second connecting rod is fixedly connected with the center of mass of the underwater target in the angular direction, or one end of the second connecting rod is connected with one end of the first connecting rod in the angular direction, and the other end of the second connecting rod is connected with the support structure, and the angular direction is a direction with an included angle of with the Z axis in the XZ plane. S3, determining the force exerted by the internal solitary wave on the center of mass of the underwater target along the X-axis direction based on the measurement results of the first force and the second force the component of the second force in the direction of the second connecting rod balances the component of the first force in the direction of the first connecting rod.​​​​​ The first connecting rod and the second connecting rod are in a split structure or are fixedly connected in an integral structure. When the first connecting rod and the second connecting rod are in the split structure, the second connecting rod is fixedly connected with the centroid of the underwater target along the angular direction. When the first connecting rod and the second connecting rod are fixedly connected in the integral structure, one end of the second connecting rod is connected with one end of the first connecting rod along the angular direction, and the other end of the second connecting rod is connected with the support structure.

2. The internal solitary wave force measurement method according to claim 1, wherein: When the first connecting rod and the second connecting rod are in a split structure, the first connecting rod and the second connecting rod are connected by a hinge The upper limit of the angle is determined based on a measurement result of the first acting force The first force arm of the second force gauge And the anti-torque limit of the second force gauge Determination The The upper limit of the angle is derived according to the following formula, ， wherein, is the measurement result of the first load cell, is the empirical value of the maximum acting force of the internal solitary wave along the X-axis direction, is the distance of the second load cell to the mass center of the underwater target, is the anti-torque limit of the second load cell.

3. The internal solitary wave force measurement method according to claim 2, wherein: When the first link and the second link are separate structures, the second link in the XZ plane and the Z-axis... Given a fixed angle, the installation position of the second force gauge relative to the second connecting rod can be determined by calculating the lever arm. The limit value is set, and the lever arm is... Determined according to the following formula, ， wherein, is the measurement result of the first load cell, is the empirical value of the maximum acting force of the internal solitary wave along the X-axis direction, is the anti-torque limit of the second load cell.

4. The internal solitary wave force measurement method according to claim 1, wherein: When the first connecting rod and the second connecting rod are fixedly connected as an integrated structure, the first connecting rod and the second connecting rod are The upper limit of the angle is based on the maximum force exerted by the internal solitary wave in the Z-axis direction The second force arm of the second load cell And the anti-torque limit of the second load cell Determination; The The upper limit of the angle is derived according to the following formula, ， wherein, is an empirical value of the maximum force exerted by the internal solitary wave along the Z-axis direction, is an empirical value of the maximum force exerted by the internal solitary wave along the X-axis direction, is the distance from the second force gauge to the inflection point A where the first and second links intersect along the direction in which the second link lies, is the anti-torque limit of the second force gauge.

5. The internal solitary wave force measurement method according to any one of claims 2 or 4, wherein, A step S12 is further included between the step S1 and the step S2: based on adjusting an angle between the second link and the Z axis in the XZ plane based on the upper limit of the angle.

6. The internal solitary wave force measurement method according to claim 5, wherein: A step S13 is further included between the step S12 and the step S2, Based on the position of the underwater target in S1, the length of the second connecting rod in the XZ plane is adjusted to keep the depth information and position information of the underwater target in the experimental pool unchanged.

7. The internal solitary wave force measurement method according to claim 1, wherein: The first force gauge and / or the second force gauge are arranged close to the center of mass of the underwater target and above the liquid surface of the experimental pool.

8. The internal solitary wave force measurement method according to claim 1, wherein: The force balance equation along the direction of the second connecting rod is decomposed, and the force of the internal solitary wave along the X-axis direction is obtained according to the following formula , ， wherein, is the internal solitary wave force on the first load cell in the direction of the Z axis, , is the internal solitary wave force on the second load cell in the direction of the second link, .

9. The internal solitary wave force measurement method according to claim 1, wherein: The internal solitary waves applied in the step S1 and the step S2 are of the same characteristics.

10. The internal solitary wave force measurement method according to claim 1, wherein: The forces measured in the step S1 and the step S2 are measured when the underwater target is in a state of balance between gravity and buoyancy in the experimental pool.

11. The internal solitary wave force measurement method according to claim 4, wherein: When the first connecting rod and the second connecting rod are of an integrated structure, a measuring device is used to measure the internal solitary wave, the measuring device comprising the first connecting rod, the second connecting rod, a force transmission part, a support structure, and an adjusting and limiting mechanism, the support structure being arranged above the experimental pool, the force transmission part being of a hinged structure, and the adjusting and limiting mechanism being slidably connected to a support unit of the support structure; The adjusting and limiting mechanism comprises a first limiting block and a second limiting block, the first limiting block being fixedly connected to the support structure, and the second limiting block being rotatably connected to one side of the first limiting block along the Y-axis direction, the rotation direction being parallel to the XZ plane; The first connecting rod comprises a first upper connecting rod and a first lower connecting rod fixedly connected to both ends of the first force gauge along the Z-axis direction, the other end of the first lower connecting rod being fixedly connected to the center of mass of the underwater target, and the other end of the first upper connecting rod being connected to the force transmission part. The second connecting rod comprises a first end fixedly connected to the second force gauge and a second end fixedly connected to the first connecting rod The second upper connecting rod and the second lower connecting rod are fixedly connected at two ends of the second force gauge in the angular direction, respectively, wherein the second upper connecting rod is connected to the support structure through the first limiting block, and the second lower connecting rod is fixedly connected to the first upper connecting rod through the force transmission part.

12. The internal solitary wave force measurement method according to claim 4, wherein: When the first connecting rod and the second connecting rod are of an integrated structure, a measuring device is used to measure the internal solitary wave, the measuring device comprising the first connecting rod, the second connecting rod, a force transmission part, and a support structure, the support structure being arranged above the experimental pool; The force transmission part comprises an integrated connecting piece composed of a first connecting part, a corner part, and a second connecting part. The first connecting rod comprises a first upper connecting rod and a first lower connecting rod fixedly connected at two ends of the first force gauge in the Z-axis direction, the other end of the first lower connecting rod is fixedly connected with the center of mass of the underwater target, and the other end of the first upper connecting rod is connected with the first connecting part of the force transmission part; The second link includes a second upper link, one end of which is along... One end is connected to the support structure at an angle, and the other end is connected to one end of the second force gauge. The other end of the second force gauge is connected to the second connecting part of the force transmission part.

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