Underwater grounding structure stress experiment device suitable for different water flow conditions and measurement method

Abstract

The invention relates to an underwater grounding structure stress experiment device suitable for different water flow conditions and a measurement method. The underwater grounding structure stress experiment device comprises a structure, a force sensor, a false bottom, an elastic support and water flow detection equipment, the number of the force sensors is two. The two force sensors are installed at the two ends of the structure respectively and used for fixing the structure and detecting the stress condition of the structure. The false bottom is arranged below the structure; the false bottom is provided with two through holes; the number of the elastic supports is two. The two elastic supports respectively penetrate through the two through holes and are respectively connected with the two force sensors; the water flow detection equipment is arranged near the structure and is used for collecting the flow velocity of water; the device is reasonable in structure and convenient to disassemble, can be suitable for different water flow conditions, can accurately measure the stress of various underwater grounding structures in ocean engineering, and improves the measurement precision and reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater structures in marine engineering, and specifically relates to a force test device and a measurement method for underwater bottom-touching structures suitable for different water flow conditions. Background Art

[0002] In marine engineering, the stability of underwater structures touching the bottom is directly related to the safety and reliability of marine facilities. However, existing force measurement methods have some limitations. Traditional measurement methods rely on fixed sensor arrays, which are not accurate or flexible enough when water flow conditions change.

[0003] With the continuous development of marine resources, it is particularly important to understand the engineering mechanical properties of underwater bottom-touching structures. Underwater bottom-touching structures are subject to the combined effects of gravity, hydrodynamics and their own dynamics during operation. When the water flow conditions change, the actual corresponding forces on the underwater bottom-touching structures change. Therefore, the study of bottom-touching structures under different water flow conditions is crucial to the safety of the installation of underwater working systems.

[0004] The Chinese invention patent with the announcement number "CN111398036A" discloses an intelligent towing test system for measuring the stress of the submarine structure, which simulates the stress of the structure when the fishing boat drags the hook, quickly and accurately realizes the stress analysis of the submarine protection structure, and obtains the load on the submarine protection structure. However, it mainly considers the stress changes caused by the different real-time towing speeds of the fishing boat, and does not consider the impact of water flow changes.

[0005] The Chinese invention patent with the announcement number "CN115307871A" discloses an embedded force measurement method for the interaction between an underwater structure and an internal solitary wave, which uses a force sensor to measure the three-dimensional force data of the structure model when the internal solitary wave passes through; the depth of the structure model in the laboratory water tank is changed by a telescopic rod with adjustable length. However, the telescopic rod is only used to measure the interaction force between the underwater structure model and the internal solitary wave propagating at different underwater depths, which is aimed at the research on the water depth level, rather than the research on the water flow conditions.

[0006] In summary, the existing technology has limitations in measurement accuracy and application scope in the measurement of forces on underwater bottom-touching structures, and a new measurement method is needed to improve the accuracy and reliability of the measurement. Summary of the invention

[0007] In response to at least one of the problems in the above-mentioned prior art, the purpose of the present invention is to provide an underwater bottom-touching structure force experimental device and measurement method suitable for different water flow conditions, so as to overcome the limitations of the prior art in the measurement of underwater bottom-touching structure force and the scope of application, and improve the accuracy and reliability of the measurement.

[0008] To achieve the above object, the present invention adopts the following technical solutions: An underwater bottom-touching structure force test device suitable for different water flow conditions, comprising: structures; The force sensors are provided in two numbers; the two force sensors are respectively installed at two ends of the structure, and are used to fix the structure and detect the force condition of the structure; A false bottom is arranged below the structure; the false bottom is provided with two perforations; The elastic supports are provided in two numbers; the two elastic supports respectively pass through the two through holes and are respectively connected to the two force sensors; The water flow detection equipment is arranged near the structure and is used to collect the water flow rate.

[0009] Preferably, a telescopic mechanism is provided on the top of the elastic support for adjusting the gap distance between the structure and the false bottom.

[0010] Preferably, the false bottom is configured as a rigid material layer.

[0011] Preferably, the false bottom is laid on the bottom surface of the sink.

[0012] Preferably, the false bottom covers the entire bottom surface of the sink.

[0013] Preferably, a collection device is connected to the two force sensors to collect the force data transmitted back by the force sensors.

[0014] Preferably, it is characterized in that the structure is arranged in a columnar shape.

[0015] A method for measuring the force of an underwater bottom-touching structure suitable for different water flow conditions is implemented based on any of the above-mentioned experimental devices, comprising the following steps: Placing the water flow monitoring device near the structure 1, and turning on the power of the acquisition device and the water flow monitoring device; After the water flow stabilizes, read the water flow rate data of the water flow monitoring device to obtain the water flow rate V; calculate the Reynolds number according to the formula, Re=ρVL / μ Wherein, ρ is the water density, L is the characteristic length of the structure, and μ is the dynamic viscosity of the water; Determine the size of the Reynolds number Re and the characteristic Reynolds number, and when the Reynolds number Re≤characteristic Reynolds number, adjust the top length of the elastic support so that the gap distance between the structure and the false bottom is a set multiple of the characteristic length of the structure; when the Reynolds number Re>characteristic Reynolds number, adjust the top length of the elastic support to reduce the gap distance between the structure and the false bottom to 0; The force data of the force sensor is collected and recorded, and processed to obtain the force condition of the structure.

[0016] Preferably, when the structure is columnar, its characteristic length is the cross-sectional diameter.

[0017] Preferably, the characteristic Reynolds number is 3900, and the gap distance between the structure and the false bottom is a set multiple of the characteristic length of the structure that is ≤0.01 times.

[0018] The present invention adopts the above technical solution, which has the following advantages: The present invention provides an underwater bottom-touching structure force experimental device and measurement method suitable for different water flow conditions. By obtaining the Reynolds number at the current flow rate and comparing it with the characteristic Reynolds number, the next step to be taken for the experimental device is determined, and then the experimental device configuration that better meets the current water flow conditions is obtained. When the Reynolds number Re≤characteristic Reynolds number, the top length of the elastic support is adjusted so that the gap distance between the structure and the false bottom is 0.01 times the characteristic length of the structure; when the Reynolds number Re>characteristic Reynolds number, the top length of the elastic support is adjusted to minimize the gap distance between the structure and the false bottom, thereby improving the reliability of the measurement results and the measurement accuracy; the experimental device has a simple structure, is easy to load and unload, and is convenient for physical model experiments. It can be applied to different water flow conditions and can perform relatively accurate force measurements on various underwater bottom-touching structures in marine engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front view of an underwater bottom-touching structure force test device suitable for different water flow conditions provided by one embodiment of the present invention.

[0020] Figure 2 It is a top view of an underwater bottom-touching structure force test device suitable for different water flow conditions provided by an embodiment of the present invention.

[0021] Figure 3 It is a side view of an underwater bottom-touching structure force test device suitable for different water flow conditions provided by one embodiment of the present invention.

[0022] Figure 4 It is a schematic diagram of the application state of an underwater bottom-touching structure force test device suitable for different water flow conditions provided by an embodiment of the present invention.

[0023] Figure 5 It is a flow chart of a method for measuring the force of an underwater bottom-touching structure applicable to different water flow conditions provided by an embodiment of the present invention.

[0024] Markings in the accompanying drawings: 1. Structure, 2. Force sensor, 3. False bottom, 4. Elastic support, 5. Water tank. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention. The direction of the arrow in the figure represents the direction of liquid flow.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "assembly", "setting", and "connection" 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 or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention provides an underwater bottom-touching structure force experimental device suitable for different water flow conditions. By obtaining the Reynolds number at the current flow rate and comparing it with the characteristic Reynolds number, the next step to be taken for the experimental device is determined, and then the experimental device configuration that better meets the current water flow conditions is obtained. The device can be suitable for different water flow conditions and can perform relatively accurate force measurements on various underwater bottom-touching structures in marine engineering. The device can overcome the limitations of the prior art in measurement accuracy and application scope in underwater bottom-touching structure force measurements, and improve measurement accuracy and reliability. The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0029] Example 1 Please refer to Figures 1 to 4 The underwater bottom-touching structure force experimental device provided in this embodiment, which is suitable for different water flow conditions, includes a structure 1, a force sensor 2, a false bottom 3, an elastic support 4 and a water flow detection device; the force sensor 2 is set to two; the two force sensors 2 are respectively installed at both ends of the structure 1, for fixing the structure 1 and detecting the force condition of the structure 1; the false bottom 3 is set below the structure 1; the false bottom 3 is provided with two through holes; the elastic support 4 is set to two; the two elastic supports 4 pass through the two through holes respectively, and are respectively connected to the two force sensors 2; the water flow detection device is set near the structure 1, for collecting the flow rate of water.

[0030] Among them, the water flow detection equipment can adopt existing technology products, and can obtain the speed, direction and turbulence of the water flow in real time. For example, the water flow detection equipment can adopt laboratory flow velocity sensors, Doppler flow meters, etc., or engineering propeller flow velocity meters, ultrasonic flow velocity meters, radar flow velocity meters, etc.

[0031] The structure 1 may be a submarine cable. The force sensor 2 may be clamped at both ends of the structure 1 by bolts to detect the stress of the structure 1 under different water flow conditions.

[0032] Specifically, a telescopic mechanism is provided at the top of the elastic support 4 to adjust the gap distance between the structure 1 and the false bottom 3. Therefore, it can be determined according to the Reynolds number whether the telescopic mechanism needs to be extended or shortened to change the top length of the elastic support 4, thereby changing the gap distance between the structure 1 and the false bottom 3. The elastic support 4 can be an engineering term in the field of civil engineering in the prior art, which refers to a support that will undergo elastic deformation after being subjected to force.

[0033] Specifically, the false bottom 3 is configured as a rigid material layer that is not easily deformed, and the false bottom 3 may be a flat plate.

[0034] like Figure 4 As shown, the false bottom 3 can also be laid on the bottom surface of the water tank 5 in detail.

[0035] For example, the false bottom 3 covers the entire bottom surface of the water tank 5 .

[0036] Please refer to Figures 1 to 4 Specifically, the acquisition device is connected to the two force sensors 2 and is used to collect the force data transmitted back by the force sensors 2 .

[0037] Specifically, the structure 1 is configured to be columnar.

[0038] Example 2 Please refer to Figures 1 to 5 A method for measuring the force of an underwater bottom-touching structure suitable for different water flow conditions is implemented based on the experimental device described in Example 1, comprising the following steps: Step S1, placing a water flow monitoring device near the structure 1, and turning on the power of the acquisition device and the water flow monitoring device; Step S2, after the water flow is stable, read the water flow rate data of the water flow monitoring device to obtain the water flow rate V; calculate the Reynolds number according to formula (1); Re = ρVL / μ (1) Where ρ is the water density, L is the characteristic length of structure 1, and μ is the dynamic viscosity of the water; Step S3, judging the size of the Reynolds number Re and the characteristic Reynolds number, when the Reynolds number Re≤the characteristic Reynolds number, adjusting the top length of the elastic support 4 so that the gap distance between the structure 1 and the false bottom 3 is a set multiple of the characteristic length of the structure 1; when the Reynolds number Re>the characteristic Reynolds number, adjusting the top length of the elastic support 4 to reduce the gap distance between the structure 1 and the false bottom 3 to 0; Step S4: collecting and recording the force data of the force sensor 2, and processing the data to obtain the force condition of the structure 1.

[0039] In step S1, ρ is usually set to 10 3 kg / m 3 ; L is the characteristic length of the structure, μ is usually taken as 1.01×10 3 Pa∙s.

[0040] When the structure 1 is columnar, its characteristic length is the cross-sectional diameter.

[0041] In step S3, the characteristic Reynolds number is 3900, and the gap distance between the structure 1 and the false bottom 3 is a set multiple of the characteristic length of the structure 1, which is ≤0.01 times.

[0042] In step S4, when processing the force data of the force sensor 2, the obtained force data can be multiplied by a coefficient, integrated, or post-processed in other ways according to the needs of the actual situation to obtain the force condition of the structure 1.

[0043] For example, the size of the Reynolds number Re and the characteristic Reynolds number 3900 is judged. When the Reynolds number Re≤3900, the top length of the elastic support 4 is adjusted to make the gap distance between the structure 1 and the false bottom 3 0.01 times the characteristic length of the structure 1 to ensure the accuracy of the force measurement of the structure 1; when the Reynolds number Re>3900, the top length of the elastic support 4 is adjusted to reduce the gap distance between the structure 1 and the false bottom 3 as much as possible to ensure the accuracy of the force measurement of the structure 1.

[0044] The acquisition device, also known as a data collector, can collect, store and transmit data, convert physical quantities such as velocity, acceleration, displacement, etc. into digital signals and store them in memory, and then transmit them to a computer system or the like through a wired or wireless network for further analysis. The acquisition device can also be connected to the force sensor 2 through a wired or wireless mode.

[0045] The Reynolds number is a dimensionless number that can be used to characterize the flow of a fluid. The Reynolds number can be used to distinguish between laminar and turbulent flow states of a fluid, and can also be used to determine the resistance to the flow of an object in a fluid.

[0046] Characteristic Reynolds number, used to help determine the state of the water flowing beneath the structure, such as laminar or turbulent flow.

[0047] The force experimental device and measurement method of underwater bottom-touching structures provided in this embodiment, which are suitable for different water flow conditions, can be used for physical model experiments and practical engineering guidance, as well as for numerical simulation. In the process of numerical simulation, it is necessary to consider both accuracy and calculation complexity. By studying the influence of gap ratio / embedding ratio on hydrodynamic and flow characteristics, it is concluded that when the gap ratio is less than 0.01, when the Reynolds number is lower than the characteristic Reynolds number requirement, the gap ratio can be formed to form a sealed gap, the structure 1 is partially buried in the real or simulated seabed bottom, or an open gap is formed. The value of the gap ratio has little effect on the calculation accuracy, but the formation of a sealed gap or the partial burial of the structure 1 in the bottom can significantly reduce the calculation cost. The gap ratio is the ratio of the gap from the bottom of the structure 1 to the false bottom 3 to the characteristic length of the structure 1; under higher Reynolds number requirements, the gap ratio needs to be reduced as much as possible to ensure that the calculation accuracy is not reduced.

[0048] The sealed gap means that the gap between the structure 1 and the false bottom 3 is 0. The open gap means that the gap between the structure 1 and the false bottom 3 is greater than 0.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An underwater bottom-touching structure force test device suitable for different water flow conditions, characterized in that: include: Structure (1); Force sensors (2), provided in two numbers; The two force sensors (2) are respectively mounted at two ends of the structure (1) and are used to fix the structure (1) and detect the force applied to the structure (1); A false bottom (3) is arranged below the structure (1); the false bottom (3) is provided with two perforations; The elastic supports (4) are provided in two numbers; the two elastic supports (4) respectively pass through the two through holes and are respectively connected to the two force sensors (2); The water flow detection equipment is arranged near the structure (1) and is used to collect the water flow rate.

2. The underwater bottom-touching structure stress test device applicable to different water flow conditions according to claim 1 is characterized in that: A telescopic mechanism is provided on the top of the elastic support (4) for adjusting the gap distance between the structure (1) and the false bottom (3).

3. The underwater bottom-touching structure stress test device applicable to different water flow conditions according to claim 1 is characterized in that: The false bottom (3) is configured as a rigid material layer.

4. The underwater bottom-touching structure stress test device applicable to different water flow conditions according to claim 3 is characterized in that: The false bottom (3) is laid on the bottom surface of the water tank (5).

5. The underwater bottom-touching structure stress test device applicable to different water flow conditions according to claim 4 is characterized in that: The false bottom (3) covers the entire bottom surface of the water tank (5).

6. The underwater bottom-touching structure stress test device applicable to different water flow conditions according to claim 1 is characterized in that: The acquisition device is connected to the two force sensors (2) and is used to acquire the force data transmitted back by the force sensors (2).

7. The underwater bottom-touching structure force test device applicable to different water flow conditions according to any one of claims 1 to 6, characterized in that: The structure (1) is configured in a columnar shape.

8. A method for measuring the force of an underwater bottom-touching structure suitable for different water flow conditions, characterized in that: The experimental device according to any one of claims 1 to 7 is implemented, comprising the following steps: Placing the water flow monitoring device near the structure 1, and turning on the power of the acquisition device and the water flow monitoring device; After the water flow stabilizes, read the water flow rate data of the water flow monitoring device to obtain the water flow rate V; calculate the Reynolds number according to formula (1): Re = ρVL / μ (1) Wherein, ρ is the water density, L is the characteristic length of the structure (1), and μ is the dynamic viscosity of the water; Determine the size of the Reynolds number Re and the characteristic Reynolds number. When the Reynolds number Re≤the characteristic Reynolds number, adjust the top length of the elastic support (4) so ​​that the gap distance between the structure (1) and the false bottom (3) is a set multiple of the characteristic length of the structure (1); when the Reynolds number Re>the characteristic Reynolds number, adjust the top length of the elastic support (4) so ​​that the gap distance between the structure (1) and the false bottom (3) is reduced to 0; The force data of the force sensor (2) is collected and recorded, and processed to obtain the force condition of the structure (1).

9. The method for measuring the force of an underwater bottom-touching structure applicable to different water flow conditions according to claim 8, characterized in that: When the structure (1) is columnar, its characteristic length is the cross-sectional diameter.

10. The method for measuring the force of an underwater bottom-touching structure applicable to different water flow conditions according to claim 8 or 9, characterized in that: The characteristic Reynolds number is 3900, and the gap distance between the structure (1) and the false bottom (3) is a set multiple of the characteristic length of the structure (1) of ≤0.01 times.

Images