Internal solitary wave force measurement device, system and method

Abstract

The present application provides an internal solitary wave force measurement device, system and method. The measurement device is used to measure the internal solitary wave force exerted on an underwater target arranged in an experimental water pool, and includes a support structure and a measurement unit. The support structure is used to support the measurement unit. The measurement unit includes a first measurement unit, a second measurement unit and a force transmission unit. The first measurement unit is used to measure the vertical force exerted on the center of mass of the underwater target by the internal solitary wave, and is used to transmit the horizontal force exerted on the center of mass of the underwater target by the internal solitary wave, wherein the positive direction of the horizontal force is the propagation direction of the internal solitary wave. The force transmission unit is virtually connected to the first measurement unit and fixedly connected to the second measurement unit, and is used to amplify and transmit the horizontal force to the second measurement unit. The second measurement unit is used to measure the amplified horizontal force. The technical solution of the present application can accurately measure the vertical force and horizontal force of the internal solitary wave.

Description

Technical Field

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

[0002] The density, salinity and temperature of real fluids in the ocean often change with depth, that is, they are generally stratified fluids. Internal waves are disturbances existing in stratified fluids. When a submerged body encounters an ocean internal wave with a wavelength of 1 to 2 times the length of the submerged body, the internal wave has a greater impact on the submerged body and is prone to danger; among the many types of internal waves, ocean internal waves in this wavelength range are usually internal solitary waves. As a special nonlinear internal wave, the wave height of internal solitary waves is often large and widely distributed in the global ocean. During the propagation of internal solitary waves, it will cause strong convergence and divergence of seawater and sudden strong currents, which will produce shearing effects on submerged bodies crossing the pycnocline. When a submerged body resting on the pycnocline fluctuates up and down with the internal solitary waves at the pycnocline, its position may be exposed when the distance between the submerged body and the sea surface becomes smaller, or it may be pressed to below the limit depth of the submerged body and destroyed by the huge seawater pressure, causing accidents. It can be seen that internal solitary waves will have a great impact on the stability and maneuverability of the submerged body. Therefore, it is of great value to study the influence of internal solitary waves on the hydrodynamic performance of underwater submerged bodies.

[0003] In addition to using numerical simulation to study the interaction between internal solitary waves and submerged bodies, water tank experiments can also be used to measure the internal solitary wave forces on underwater targets such as submerged body models. For example, Patent 201810114516.7 discloses an experimental system for the interaction between internal waves and submerged bodies. Three pressure sensors arranged on the head, middle and side of the submerged body model are used to measure the forces in three directions respectively. However, the measurement position of the above method is the surface of the submerged body model, and the force condition at its center of mass cannot be directly obtained. At the same time, due to the characteristics of internal solitary waves, the forces in the horizontal and vertical directions may differ by an order of magnitude. In order to ensure the accuracy of the experiment, sensors with different ranges and accuracies are required. The price and usage cost of the experimental equipment have increased; for example, patent 202211064910.7 proposes an embedded force measurement method for the interaction between underwater structures and internal solitary waves. The force sensor is embedded in the underwater structure model, and the three-dimensional force data of the structure model when the internal solitary wave passes is measured. However, multi-component force sensors that meet the requirements of one-tenth of the horizontal force and vertical force precision and range generally need to be customized separately, and their price is much higher than that of single-component force sensors. In addition, the sensor is built into the underwater submersible model in its solution. Since the fluid environment of the experiment usually contains oil and water, the complexity of operations such as sensor installation and sealing is greatly increased, which undoubtedly increases the probability of sensor damage.

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

[0005] In order to solve the problems existing in the above-mentioned prior art, the present application provides an internal solitary wave force measurement device through an embodiment, which is used to measure the internal solitary wave force exerted on an underwater target arranged in an experimental water pool, and includes a support structure and a measuring unit, wherein the support structure is used to support the measuring unit, and the measuring unit includes a first measuring part, a second measuring part and a force transmission part; the first measuring part is used to measure the vertical force exerted on the center of mass of the underwater target by the internal solitary wave, and is used to transmit the horizontal force exerted on the center of mass of the underwater target by the internal solitary wave, wherein the positive direction of the horizontal force is the propagation direction of the internal solitary wave; the force transmission part is virtually connected with the first measuring part, and is fixedly connected with the second measuring part, and is used to amplify the horizontal force and transmit it to the second measuring part; the second measuring part is used to measure the amplified horizontal force.

[0006] Further, the first measuring part includes a first dynamometer, and an upper connecting rod and a lower connecting rod fixedly connected to both sides of the first dynamometer along the vertical direction, wherein the upper connecting rod is rotatably connected to the support structure, and the direction of its rotation axis is perpendicular to both the vertical direction and the propagation direction of the internal solitary wave, and the lower connecting rod is fixedly connected to the underwater target, and its lower end is located at the center of mass of the underwater target; the second measuring part includes a second dynamometer, and a front connecting rod and a rear connecting rod fixedly connected to both sides of the second dynamometer along the propagation direction of the internal solitary wave, wherein the front connecting rod is fixedly connected to the force transmission part, and the rear connecting rod is detachably fixedly connected to the support structure.

[0007] Preferably, the distance from the center of mass of the underwater target to the rotation axis of the upper connecting rod is 4 to 12 times the distance from the force transmission part to the rotation axis of the upper connecting rod.

[0008] Preferably, the force transmission part includes a virtual connection part, which has a virtual connection channel running through in the vertical direction, and one of the upper connecting rod or the lower connecting rod passes through the virtual connection channel and is virtually connected with the virtual connection channel; the front connecting rod is fixedly connected to the virtual connection part.

[0009] Furthermore, the virtual connection is specifically:

[0010] 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 apply a horizontal force to the virtual connection portion;

[0011] When the deviation between the central axis of the connecting rod passing through the virtual connection channel and the central axis of the virtual connection channel exceeds a preset deviation threshold, the connecting rod passing through the virtual connection channel applies a horizontal force to the virtual connection portion.

[0012] Preferably, the force transmission portion further comprises a connecting portion, wherein one end of the connecting portion facing the front connecting rod is fixedly connected to the front connecting rod, and one end of the connecting portion facing away from the front connecting rod is fixedly connected to the virtual connection portion.

[0013] Preferably, the length of the virtual connection channel is smaller than the diameter of the front connecting rod.

[0014] Preferably, the connecting rod passing through the virtual connection channel is a cylindrical rod, and the virtual connection portion is configured as a ring having a circular or elliptical cross-section.

[0015] Preferably, the connecting rod passing through the virtual connection channel is a rectangular rod, and the virtual connection portion is constructed as a rectangular ring with a wedge-shaped cross section.

[0016] Preferably, a fixing groove is formed at one end of the connecting portion facing the front connecting rod, and one end of the front connecting rod facing the connecting portion is fixedly connected to the connecting portion by being inserted into the fixing groove.

[0017] Preferably, the portion of the connecting rod passing through the virtual channel inside the virtual channel is coated with lubricating material.

[0018] Preferably, the first force gauge is located below the virtual connection channel.

[0019] Furthermore, the support structure is arranged above the experimental water pool, and includes a longitudinal support unit, a transverse support unit, a vertical support unit that cooperate with each other, 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.

[0020] A hinged portion is provided on the lower surface of the upper top plate, and 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.

[0021] 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.

[0022] The present application also provides an internal solitary wave force measurement system through an embodiment, including an experimental water pool, a wave-making mechanism, a wave-breaking mechanism and an underwater target, wherein the experimental water pool is filled with at least two liquids with different densities, the wave-making mechanism is used to generate an internal solitary wave propagating at the interface of the two liquids with different densities, and the wave-breaking mechanism is used to eliminate the internal solitary wave; the measurement system also includes the aforementioned internal solitary wave force measurement device, which is used to measure the internal solitary wave force exerted on the underwater target.

[0023] The present application also provides an internal solitary wave force measurement method through an embodiment. The method uses the aforementioned internal solitary wave force measurement system to measure the internal solitary wave force exerted on an underwater target, and comprises the following steps:

[0024] Preliminarily assembling the support device, the first measuring part, the second measuring part, and the force transmission part in the internal solitary wave force measurement device;

[0025] Adjusting the positions of the first measuring part, the second measuring part and the force transmitting part so that the force transmitting part is in virtual contact with the first measuring part;

[0026] The lower end of the first measuring part is fixedly connected to the center of mass of the underwater target, and the underwater target is placed in a state of gravity and buoyancy balance in the experimental pool by adjusting the counterweight;

[0027] generating internal solitary waves in the experimental water tank;

[0028] respectively performing measurement 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;

[0029] Determine, based on the measurement result of the first measurement unit, the vertical force exerted on the center of mass of the underwater target by the internal solitary wave;

[0030] The horizontal force exerted by the internal solitary wave on the center of mass of the underwater target is determined based on the measurement result of the second measuring part and the magnification, wherein the magnification is determined based on the position where the force transmission part is virtually connected to the first measuring part.

[0031] Preferably, before the lower end of the first measuring part is fixedly connected to the center of mass of the underwater target, the method further comprises the following steps:

[0032] A plurality of groups of standard weights with different masses are sequentially hung at the lower end of the first measuring part to apply force thereto in the vertical direction, and an error correction value of the first measuring part is determined based on each measurement result of the first measuring part, and the error correction value is used to correct the vertical force;

[0033] A plurality of groups of standard weights with different masses are sequentially hung at the lower end of the first measuring part to exert force thereon in a horizontal direction, and the magnification is determined based on each measurement result of the second measuring part.

[0034] The embodiment of the present application provides an internal solitary wave force measurement device, in which the force transmission part is virtually connected to the vertical first measuring part and is fixedly connected to the horizontal second measuring part. The vertical force of the internal solitary wave is directly collected through this connection method, and the horizontal force of the internal solitary wave is amplified and transmitted to the second measuring part by utilizing the rotatability of the first measuring part relative to the supporting structure, so that the magnitudes of the components of the internal solitary wave force in each direction are within a consistent magnitude range, so that high-precision single-component force sensors with multiple ranges and consistent accuracy can be used to measure the components of the internal solitary wave in each direction. Compared with the existing scheme, there is no need to select multiple sensors of different specifications, and it is avoided that when only one multi-component force sensor is set at the center of mass, 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 separately customized. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the arrangement of sensors for testing the internal solitary wave force on an underwater target;

[0036] Figure 2a A schematic diagram of the arrangement of sensors for testing the internal solitary wave force on an underwater target;

[0037] Figure 2b It is a schematic diagram of the principle of a multi-component force sensor;

[0038] Figure 3 A schematic diagram of the layout of an internal solitary wave force measurement system provided according to an embodiment of the present application;

[0039] Figure 4 It is a structural schematic diagram of an internal solitary wave force measurement device provided according to an embodiment of the present application;

[0040] Figure 5 for Figure 4 An enlarged schematic diagram of the middle circle A;

[0041] Figure 6 It is a side view of the internal solitary wave force measurement device provided according to an embodiment of the present application;

[0042] Figure 7 for Figure 6 An enlarged schematic diagram of the middle circle B;

[0043] Figure 8 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0044] Fig. 9 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0045] Fig.10 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0046] Fig.11 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0047] Fig.12 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0048] Fig.13 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0049] Fig.14 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0050] Fig.15 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0051] Fig.16 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0052] Fig.17 A side view of a force transmission portion provided according to an embodiment of the present application;

[0053] Fig.18 It is a structural schematic diagram of a force transmission part provided according to an embodiment of the present application;

[0054] Fig.19 A cross-sectional view of a force transmission portion provided according to an embodiment of the present application;

[0055] Fig. 20 A side view of a force transmission portion provided according to an embodiment of the present application;

[0056] Fig.21 It is a structural schematic diagram of an internal solitary wave force measurement device provided according to an embodiment of the present application;

[0057] Fig. 22 It is a flow chart of the internal solitary wave force measurement method provided according to an embodiment of the present application;

[0058] Fig.23a A schematic diagram of calibrating an internal solitary wave force measurement device according to an embodiment of the present application;

[0059] Figure 23b for Fig.23aThe enlarged schematic diagram of the middle circle C;

[0060] Fig.23c A pictorial diagram of pulley arrangements in some embodiments;

[0061] Fig.24 In a specific embodiment, the measurement data of the standard weight obtained by the first measuring part;

[0062] Fig.25 In a specific embodiment, the measurement data of the standard weight obtained by the second measuring part;

[0063] Fig.26 is a schematic diagram of the change of the vertical force of a solitary wave in a specific embodiment;

[0064] Fig. 27 FIG. 4 is a schematic diagram showing the change of the horizontal force of a solitary wave after amplification in a specific embodiment.

[0065] Numbers in the figure

[0066] First measuring part 1, upper connecting rod 11, lower connecting rod 12, first dynamometer 13, 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, hinge seat 441, rotating shaft 44 2, bearing 443, side plate 45, adjustment limit mechanism 451, sleeve 4511, limit pin 4512, 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, internal solitary wave force measuring device 8, underwater target 9, center of mass 91, measuring point 901, measuring point 902, measuring point 903. DETAILED DESCRIPTION

[0067] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] Figure 1 The present invention shows a scheme for measuring the force of internal solitary waves in a water tank experiment, in which a plurality of force sensors are arranged on the surface of an underwater target 9, wherein the underwater target 9 may be a scaled-down model of a real underwater submersible. Without loss of generality, in the 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, and the Y-axis direction is another horizontal direction perpendicular to the X-axis. Obviously, the X, Y, and Z axes are orthogonal to each other.

[0073] 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:

[0074] 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;

[0075] 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:

[0076] ,

[0077] 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 or When the precise measurement of The measuring range may have been exceeded; on the contrary, if the safety of the measuring range is prioritized, accurate measurement of tiny components of the force may not be possible.

[0078] Figure 2a Another measurement scheme is shown, in which the sensor is a multi-component force sensor, which can be directly set 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.

[0079] Figure 2b The force measurement principle of a six-component force sensor is shown. The six-component force sensor is a high-precision measuring instrument that can simultaneously measure the force and torque of an object on three mutually perpendicular principal axes. Therefore, it is called a six-component force sensor. Its measurement principle is based on the bridge balance of the strain gauge. The magnitude of the force and torque is calculated by measuring the resistance change of the strain gauge. In the six-component force sensor, three mutually perpendicular strain gauges are usually used as the bridge arms of the bridge, two of which are used to measure the force and torque in the X-axis and Y-axis directions, and the third strain gauge is used to measure the force and torque in the Z-axis direction. When an object is placed on the measuring platform of the six-component force sensor, the strain gauge will deform due to the action of force and torque, causing its resistance to change. By measuring the change in resistance, the magnitude of the force and torque applied to the object can be calculated.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] In addition, since the expensive multi-component force sensor needs to be placed below the liquid surface of a mixed liquid such as water and oil, in order to reduce the probability of damage to the multi-component force sensor, it is obvious that higher requirements are placed on the watertight structure of the underwater target 9.

[0084] It can be seen that how to achieve accurate, low-cost and convenient measurement of internal solitary wave force in a water tank experimental environment is an urgent problem to be solved. To this end, the present application provides an internal solitary wave force measurement device and a measurement system using the device through an embodiment, which can accurately measure the distribution characteristics of the internal solitary wave force in various directions without the need for separate customization or selection of sensors of different specifications, and the installation, debugging, use and other operations are more convenient.

[0085] Figure 3 FIG. 4 shows a schematic diagram of the layout of an internal solitary wave force measurement system provided according to some embodiments of the present application. Figure 3As shown, the system includes an experimental water pool 7 filled with at least two liquids of different densities, a wave-making mechanism and a wave-breaking mechanism (not shown in the figure) for creating and eliminating internal solitary waves in the experimental water pool, and an underwater target 9 arranged in the experimental water pool. In addition, the measurement system also includes an internal solitary wave force measurement device 8 provided according to some embodiments of the present application.

[0086] The construction method of the experimental water pool 7 is already known to those skilled in the art. For example, a frame structure of the water pool can be constructed by a plurality of horizontal water pool supports 72 and vertical water pool supports 73. Various watertight materials are used as the water pool wall 71 and the pool bottom in the frame structure to obtain the experimental water pool 7.

[0087] The experimental pool 7 is generally used as follows Figure 3 The long strip structure extending along the X-axis direction shown in the figure has a wave-generating mechanism at one end and a wave-breaking mechanism at the other end. This arrangement can generate an internal solitary wave that propagates unidirectionally along the X-axis direction at the interface of the two liquids and cut the wave when it propagates to the wave-breaking mechanism. When the internal solitary wave passes through the underwater target 9, the internal solitary wave force measurement device 8 can be used to measure the internal solitary wave force on the underwater target.

[0088] Figure 4 The structure of the internal solitary wave force measuring device 8 is shown. Figure 3 and Figure 4 As shown, the measuring device includes a measuring unit and a supporting structure 4 for supporting the measuring unit, wherein the supporting structure 4 includes a longitudinal supporting unit composed of a plurality of longitudinal brackets 41, a transverse supporting unit composed of a plurality of transverse brackets 42, a vertical supporting unit composed of a plurality of vertical brackets 43, and an upper top plate 44 arranged above the transverse supporting unit and a side plate 45 arranged on the side of the vertical supporting unit facing the propagation direction of the internal solitary wave (i.e., the direction indicated by the X-axis arrow). The longitudinal supporting unit, the transverse supporting unit and the vertical supporting 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 supporting unit can slide along the experimental water pool 7 along the X-axis direction, and the upper top plate above the transverse supporting 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.

[0089] like Figure 3 , Figure 4 As shown, the measuring unit includes a first measuring part 1, a second measuring part 2 and a force transmission part 3. Figure 5 right Figure 4 The circle A in the figure is enlarged. Figure 6 The figure shows the side view and measurement principle of the internal solitary wave force measurement device 8. Figure 7The circle B is enlarged and displayed. Figures 3 to 7 The structure and measurement principle of the measurement unit are explained in detail.

[0090] As shown in the figure, in the embodiment of the present application, the first measuring part 1 includes a first dynamometer 13, and an upper connecting rod 11 and a lower connecting rod 12 fixedly connected to both sides of the first dynamometer 13 in the vertical direction. Among them, 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 connecting rod 12 is fixedly connected to the underwater target 9. Specifically, its lower end can be extended into the underwater target 9 by threaded connection, interference fit or plug-in, and is limited after reaching the center of mass 91 of the underwater target 9.

[0091] In some embodiments, Figure 5 and Figure 6 As shown, the hinged part includes a hinged seat 441, a rotating shaft 442 and a bearing 443. The axial direction of the rotating shaft 442 is the Y-axis direction. The middle part is fixedly connected to the upper end of the upper connecting rod 11, and the two sides are sleeved in the through holes of the hinged seat 441 through bearings 443, thereby realizing a rotatable connection of the first measuring part 1 relative to the supporting structure 4.

[0092] As shown in the figure, in an embodiment of the present application, the second measuring part 2 includes a second dynamometer 23, and a front link 21 and a rear link 22 fixedly connected to both sides of the second dynamometer along the propagation direction of the internal solitary wave (the direction indicated by the X-axis arrow), wherein the rear link 22 is detachably fixedly connected to the support structure 4.

[0093] In some embodiments, Figures 4 to 7 As shown, an adjustment limit mechanism 451 is provided on the side plate 45, and 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 connecting rod 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 the limit pin 4512.

[0094] 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.

[0095] Furthermore, the first measuring part 1 and the second measuring part 2 are connected through the force transmission part 3, and the connection relationship is: the upper connecting rod 11 or the lower connecting rod 12 of the first measuring part 1 is virtually connected to the force transmission part 3, and the front connecting rod 21 of the second measuring part 2 is fixedly connected to the force transmission part 3.

[0096] Figures 8 to 20 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.

[0097] 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 the interior of the virtual connection part 31-1 has a virtual connection channel 301 that runs through the virtual connection part 31-1 in the vertical direction. The lower connecting rod 12 passes through the virtual connection channel 301 and forms a virtual connection state with the virtual connection part 31-1. At the same time, the rightmost end of the front connecting rod 21 is fixedly connected to the virtual connection part 31-1.

[0098] In the embodiments of the present application, a virtual connection refers to a connection relationship in which:

[0099] 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 apply a horizontal force to the virtual connection portion; on the other hand, when the central axis of the connecting rod passing through the virtual connection channel does not coincide with the central axis of the virtual connection channel (in the embodiment of the present application, if the deviation between the two exceeds a preset deviation threshold, it can be considered that the two no longer coincide), the connecting rod passing through the virtual connection channel applies a horizontal force to the virtual connection portion. The virtual connection relationship is described in detail below with reference to the accompanying drawings.

[0100] Combination Figure 8 and Fig. 9When the underwater target 9 is not subjected to any horizontal force, the upper connecting rod 11 and the lower connecting rod 12 of the first measuring part remain vertical under the combined force of the gravity and buoyancy of the underwater target 9. The outer diameter of the lower connecting rod 12 can be set to be slightly smaller than the inner diameter of the virtual connection channel 301, and the horizontal position of the second measuring part 2 is adjusted (this adjustment is equivalent to adjusting the horizontal position of the force transmission part 3 at the same time), so that when the central axes of the virtual connection channel 301 of the force transmission part 3 and the lower connecting rod 12 are in a coincident state, the lower connecting rod 12 does not generate any force along the X-axis direction on the virtual connection part 3 (correspondingly, the lower connecting rod 12 will not be subjected to friction in the vertical direction). Once the lower connecting rod 12 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 31-1.

[0101] 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.

[0102] Since the lower end of the lower connecting rod 12 is exactly located at the mass center 91, it is also subjected to the vertical force and horizontal force , where, since the lower connecting rod 12 and the force transmission part 3 are in virtual connection, the vertical force is directly transmitted to and collected by the first dynamometer 13; horizontal force 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 And transmitted to the front link 21, and collected by the second dynamometer 23, obviously, due to the distance from the rotating shaft 442 to the force transmission part 3 Less than its distance to the centroid 91 + ,therefore Relative to is amplified, and the theoretical value of its amplification factor is ( + ) / .

[0103] Obviously, after the length of the upper connecting rod 11 plus the first dynamometer plus the lower connecting rod 12 is determined, by reasonably setting the vertical position of the force transmission part 3, Adjust to 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.

[0104] For example, in some preferred embodiments, the distance from the center of mass 91 of the underwater target 9 to the rotation axis of the upper connecting rod 11 (i.e. + ) is the distance from the force transmission part to the rotation axis of the upper connecting rod 11 (i.e. ) is 4 to 12 times of the value. Basic and remain in the same order of magnitude, so it can be 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.

[0105] The above-mentioned cooperation between the first measuring part 1, the measuring part 2 and the force transmission part 3 can effectively solve the various problems existing in the existing measurement solutions analyzed above:

[0106] 1) The connecting rod is fixedly connected to the underwater target 9 and its end is located at the center of mass 91, so as to directly obtain the force at the center of mass 91, 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.

[0107] 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 collected by amplifying the first measuring part 1 and the upper top plate 44 by rotation connection, 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 internal solitary wave force components 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. Figure 1 The solution does not require the use of multiple sensors of different specifications. Figure 2a The solution avoids the problem that when only one multi-component force sensor is set at the center of mass 91, due to the magnitude difference of the force components in each direction, a multi-component force sensor with a wide range and high precision needs to be customized separately to ensure that the errors of each component obtained by decoupling are controlled within an acceptable range;

[0108] 3) The force gauges used to measure force are located above the water surface, making them easy to install and use, and greatly reducing the probability of equipment damage caused by placing the sensor in liquid.

[0109] Fig.10 and Fig.11Another optional embodiment of the force transmission part 3 is shown. As shown in the figure, the force transmission part 3 includes a connecting part 32 in addition to the virtual connection part 31-1. The connecting part 32 is in the shape of a step-like structure formed from the virtual connection part 31-1 to the front connecting rod 21. A fixing groove is formed at one end of the connecting part facing the front connecting rod 21. The end of the front connecting rod 21 facing the connecting part 32 is inserted into the fixing groove to form a fixed connection with the connecting part 32. The connecting part 32 can realize a more stable connection between the front connecting rod 21 and the force transmission part 3.

[0110] Fig.12 Another optional embodiment of the force transmission part 3 is shown. In this embodiment, the lower connecting rod 12 is a rectangular rod, 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 shape of the cross section of the virtual channel is also set to a rectangle matching it. Setting the connecting rod passing through the virtual channel 301 as a rectangular rod and making its surface face the propagation direction of the internal solitary wave can effectively avoid 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.

[0111] In addition, preferably, a lubricating material such as grease can be coated on the portion of the lower connecting rod 12 passing through the virtual channel 301. The lubricating material will fill the gap between the outer wall of the lower connecting rod 12 and the virtual channel 301, which can effectively avoid the problem of a large error in the horizontal force measurement result caused by a large gap between the lower connecting rod 12 and the virtual channel 301 due to manufacturing tolerances, 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 lower connecting rod 12.

[0112] Since the connection portion 32 can ensure a stable connection with the front connecting rod 21, 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 virtual connection area. For example, in some preferred embodiments, there is provided Fig.13 , Fig.14 The virtual connection portion 31 - 2 shown becomes thinner in the vertical direction. In particular, the length of the virtual connection channel 301 corresponding to the virtual connection portion 31 - 2 is smaller than the diameter of the front connecting rod 21 .

[0113] The length of the virtual connection channel 301 can be further reduced. Figures 15 to 17 As shown, in the case where the lower connecting rod 12 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. Figures 18 to 20 As shown, when the lower connecting rod 12 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 the minimum, and its side length or diameter Equal to or slightly larger than the side length or outer diameter of the lower connecting rod 12 ,at this time, and The distance can be determined more accurately, that is, Magnification factor.

[0114] Fig.21 In the illustrated embodiment, the first measuring part 1 and the second measuring part are further improved.

[0115] like Fig.21 As shown, 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 lower connecting rod 12 no longer passes through the virtual channel 301 and then connects to the first dynamometer 13, which can further reduce the influence of the contact between the connecting rod and the force transmission part on the vertical force measurement result.

[0116] 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.

[0117] In addition, in some preferred embodiments, Figure 6 As shown, an auxiliary positioning structure can also be set at the front and rear of the underwater target 9. Specifically, the auxiliary positioning structure includes two auxiliary connecting rods 461 and two corresponding rings 462. The two rings 462 are respectively mounted on the front and rear of the underwater target 9 and are respectively fixedly connected to the two auxiliary connecting rods 461. The auxiliary connecting rod 461 passes through the transverse bracket 42 matched with it, and the height can be adjusted in the vertical direction and limited by the joint. When it is necessary to deploy the measuring device, the auxiliary positioning structure can be used to provide certain auxiliary support to the underwater target 9 and ensure that its direction remains unchanged. After completing the deployment of the experimental device, the above-mentioned auxiliary positioning structure can be removed.

[0118] The present application also provides a method for measuring the internal solitary wave force, which measures the internal solitary wave force acting on an underwater target by using the aforementioned internal solitary wave force measurement system. Fig. 22 As shown, in some embodiments, the method includes the following steps:

[0119] 610, preliminarily assembling the support device, the first measuring part, the second measuring part, and the force transmission part in the internal solitary wave force measurement device;

[0120] 620, adjusting the positions of the first measuring part, the second measuring part and the force transmitting part so that the force transmitting part is in virtual contact with the first measuring part;

[0121] 630, fixedly connecting the lower end of the first measuring part to the center of mass of the underwater target, and adjusting the counterweight to make the underwater target in a state of gravity and buoyancy balance in the experimental pool;

[0122] 640, generating an internal solitary wave in the experimental water tank;

[0123] 650, respectively performing measurement 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;

[0124] 661. Determine, based on the measurement result of the first measurement unit, a vertical force exerted on the center of mass of the underwater target by the internal solitary wave;

[0125] 662. Determine 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 factor, wherein the magnification factor is determined based on the position of the virtual connection between the force transmission unit and the first measuring unit.

[0126] Since the first measuring part 1 and the second measuring part 2 obtain the vertical force and the horizontal force by direct measurement and amplified measurement respectively, in order to ensure the accuracy of the measurement results, in some preferred embodiments of the present application, the internal solitary wave measurement system also includes a calibration device 5, which is used to calibrate the internal solitary wave force measurement device before measuring the underwater target.

[0127] In some embodiments, Fig.23a , Figure 23b As 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 vertical downward force to the end, which will be fixedly connected to the center of mass 91 of the underwater target in subsequent measurements.

[0128] The standard weight 52 is also placed in the tray 53 and connected to the end of the lower connecting rod 12 through the pulley 54, so as to apply a horizontal force to the end. The installation position and installation method of the pulley 54 can be as follows: Fig.23c 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.

[0129] 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:

[0130] A plurality of groups of standard weights with different masses and applying forces to the first measuring part in a vertical direction and a plurality of groups of standard weights with different masses and applying forces to the first measuring part in a horizontal direction are sequentially hung at the lower end of the first measuring part;

[0131] An error correction value of the first measuring part is determined based on each measurement result of the first measuring part, and the error correction value is used to correct the vertical force. The magnification factor is determined based on each measurement result of the second measuring part.

[0132] Preferably, in the above calibration step, standard weights 51, 52 in two directions are placed in their respective trays 53 at the same time, that is, the vertical force for determining the error correction value of the first measuring part and the horizontal force for determining the amplification factor are applied to the end of the lower connecting rod 12 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.

[0133] exist Fig.24 , Fig.25 The measurement results of the first measuring part and the second measuring part obtained by hanging several standard weights are respectively shown. By comparing the above results with the mass of the standard weights, the error correction value of the vertical force and the amplification factor of the horizontal force can be obtained. In the subsequent internal solitary wave force measurement, the above error correction value is used to correct the vertical force, and the above amplification factor is used to amplify the horizontal force, and finally the measurement results of the vertical force and the horizontal force are obtained.

[0134] Fig.26 , Fig. 27 The vertical and horizontal forces of the internal solitary wave acting on the center of mass of the underwater target obtained from a specific experimental measurement are shown respectively. Fig.26 , Fig. 27 It can be seen that the horizontal force of the internal solitary wave is at the same order of magnitude as the vertical force after being amplified, so the same specification of force sensors can be used to accurately measure both.

[0135] The above is a detailed introduction to the specific implementation methods of the present application. For those skilled in the art, several improvements and modifications may be made to the present application without departing from the principles of the present application. These improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. An internal solitary wave force measuring device, used to measure the internal solitary wave force exerted on an underwater target arranged in an experimental water pool, comprising a support structure and a measuring unit, wherein the support structure is used to support the measuring unit, and is characterized in that: The measuring unit comprises a first measuring part, a second measuring part and a force transmitting part; The first measuring unit is used to measure the vertical force exerted by the internal solitary wave on the center of mass of the underwater target, and to transmit the horizontal force exerted by the internal solitary wave on the center of mass of the underwater target, wherein the positive direction of the horizontal force is the propagation direction of the internal solitary wave; The force transmission part is in virtual connection with the first measuring part and is fixedly connected with the second measuring part, and is used for transmitting the horizontal force to the second measuring part in an amplified manner; The second measuring part is used to measure the amplified horizontal force; The first measuring part comprises a first dynamometer, and an upper connecting rod and a lower connecting rod fixedly connected to both sides of the first dynamometer in a vertical direction, wherein the upper connecting rod is rotatably connected to the supporting structure, and the direction of its rotation axis is perpendicular to both the vertical direction and the propagation direction of the internal solitary wave, and the lower connecting rod is fixedly connected to the underwater target, and the lower end of the lower connecting rod is located at the center of mass of the underwater target; The second measuring part comprises a second dynamometer, and a front link and a rear link fixedly connected to both sides of the second dynamometer along the propagation direction of the internal solitary wave, wherein the front link is fixedly connected to the force transmission part, and the rear link is detachably fixedly connected to the support structure; The force transmission part comprises a virtual connection part, wherein the virtual connection part has a virtual connection channel penetrating in the vertical direction, and one of the upper connecting rod or the lower connecting rod passes through the virtual connection channel and is in virtual connection with the virtual connection part; The front connecting rod is fixedly connected to the virtual connection portion.

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

3. The internal solitary wave force measurement device according to claim 1, characterized in that: The virtual connection is specifically: 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 apply a horizontal force to the virtual connection portion; When the deviation between the central axis of the connecting rod passing through the virtual connection channel and the central axis of the virtual connection channel exceeds a preset deviation threshold, the connecting rod passing through the virtual connection channel applies a horizontal force to the virtual connection portion.

4. The internal solitary wave force measurement device according to claim 1, characterized in that: The force transmission part also includes a connecting part, wherein one end of the connecting part facing the front connecting rod is fixedly connected to the front connecting rod, and one end of the connecting part facing away from the front connecting rod is fixedly connected to the virtual connection part.

5. The internal solitary wave force measurement device according to claim 1, characterized in that: The length of the virtual connection channel is smaller than the diameter of the front connecting rod.

6. The internal solitary wave force measurement device according to claim 5, characterized in that: The connecting rod passing through the virtual connection channel is a cylindrical rod, and the virtual connection portion is configured as a circular ring with a circular or elliptical cross section.

7. The internal solitary wave force measurement device according to claim 5, characterized in that: The connecting rod passing through the virtual connection channel is a rectangular rod, and the virtual connection portion is configured as a rectangular ring with a wedge-shaped cross section.

8. The internal solitary wave force measurement device according to claim 1, characterized in that: The connecting rod passing through the virtual connection channel is coated with lubricating material at its portion inside the virtual connection channel.

9. The internal solitary wave force measurement device according to claim 1, characterized in that: The first force gauge is located below the virtual connection channel.

10. The internal solitary wave force measurement device according to claim 1, characterized in that: The support structure is arranged above the experimental water pool, and includes a longitudinal support unit, a transverse support unit, a vertical support unit that cooperate with each other, 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.

11. An internal solitary wave force measurement system, comprising an experimental water pool, a wave-making mechanism, a wave-breaking mechanism and an underwater target, wherein the experimental water pool is filled with at least two liquids of different densities, the wave-making mechanism is used to generate an internal solitary wave propagating at the interface of the two liquids of different densities, and the wave-breaking mechanism is used to eliminate the internal solitary wave, characterized in that: It also includes an internal solitary wave force measuring device as described in any one of claims 1 to 10, which is used to measure the internal solitary wave force exerted on the underwater target.

12. A method for measuring internal solitary wave force, using the internal solitary wave force measurement system according to claim 11 to measure the internal solitary wave force acting on an underwater target, characterized in that: The following steps are involved: Preliminarily assembling the support device, the first measuring part, the second measuring part, and the force transmission part in the internal solitary wave force measurement device; Adjusting the positions of the first measuring part, the second measuring part and the force transmitting part so that the force transmitting part is in virtual contact with the first measuring part; The lower end of the first measuring part is fixedly connected to the center of mass of the underwater target, and the underwater target is placed in a state of gravity and buoyancy balance in the experimental pool by adjusting the counterweight; generating internal solitary waves in the experimental water tank; respectively performing measurement 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; Determine, based on the measurement result of the first measurement unit, the vertical force exerted on the center of mass of the underwater target by the internal solitary wave; The horizontal force exerted by the internal solitary wave on the center of mass of the underwater target is determined based on the measurement result of the second measuring part and the magnification, wherein the magnification is determined based on the position where the force transmission part is virtually connected to the first measuring part.

13. The method for measuring internal solitary wave force according to claim 12, characterized in that: Before the lower end of the first measuring part is fixedly connected to the center of mass of the underwater target, the following steps are also included: A plurality of groups of standard weights with different masses are sequentially hung at the lower end of the first measuring part to apply force thereto in the vertical direction, and an error correction value of the first measuring part is determined based on each measurement result of the first measuring part, and the error correction value is used to correct the vertical force; A plurality of groups of standard weights with different masses are sequentially hung at the lower end of the first measuring part to exert force thereon in a horizontal direction, and the magnification is determined based on each measurement result of the second measuring part.

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