Method for simulating waves in a hypergravity field

Abstract

The present application relates to wave simulation generation technical field, specifically relates to a kind of supergravity field wave simulation method.The supergravity field wave simulation method includes: under supergravity field, the supergravity field wave making similarity relationship between predetermined wave height and frequency dimensionless quantity is verified similarity ratio;In the case where similarity ratio is consistent, the parameter of the supergravity field wave making similarity relationship is calibrated;According to the supergravity field wave making similarity relationship of calibration parameter, supergravity field wave simulation is carried out.The present application can accurately simulate the wave of different environment under supergravity field, can accurately construct transfer function, accurately assess the influence of different motion amplitude, different frequency, different gravity acceleration and other physical quantities on wave making.

Description

Technical Field

[0001] This invention relates to the field of wave simulation technology, and more specifically to a method for simulating waves in a hypergravity field. Background Technology

[0002] Wave simulation test devices under hypergravity fields are used to study the effects and damage mechanisms of waves on related structures based on the scaling effect, providing a simulation and verification platform for marine environmental research and marine resource development and application. They are mainly used to generate waves of different water depths, wave heights, and frequencies, and are a key component of wave simulation test devices. Currently, hypergravity field wave generators mainly employ push-plate and rocker-plate types. The motion and power mechanisms of these devices require a certain amount of horizontal space, reducing the effective wave generation range. Research on gravity-based wave generation under hypergravity fields is limited, and it cannot accurately simulate waves in different environments, accurately construct transfer functions, or accurately assess the impact of different motion amplitudes, frequencies, and gravitational accelerations on wave generation. Therefore, it is urgent to study wave simulation technology based on hypergravity fields, to develop methods for determining transfer functions, to provide a mapping relationship between mechanical motion and wave motion to ensure wave consistency, and to provide methods for selecting experimental parameters, thereby providing a standard marine environmental test platform for marine engineering research.

[0003] The information in the background section is merely intended to illustrate the general background of the invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] To address at least some of the technical problems in the prior art, this invention provides a method for simulating waves in a hypergravity field. Specifically, this invention includes the following:

[0005] This invention provides a method for simulating waves in a hypergravity field, the method comprising:

[0006] Under hypergravity, the similarity rate of the hypergravity wave generation similarity relationship between predetermined dimensionless quantities of wave height and frequency is verified.

[0007] If the similarity rate verification is consistent, the parameters of the wave generation similarity relationship in the hypergravity field are calibrated.

[0008] Based on the similarity relationship of wave generation in the hypergravity field with the calibration parameters, a hypergravity field wave simulation is performed.

[0009] Optionally, the wave generation similarity relationship in the hypergravity field is as follows:

[0010]

[0011] In the formula, H is the wave height, h is the liquid depth, f0 is the frequency of the device's motion, S is the amplitude of the device, and ng is the gravitational acceleration.

[0012] Optionally, the hypergravity field wave simulation method further includes:

[0013] Based on the dimensionless term, a dimensionless expression for the wave height in the hypergravity field is established.

[0014]

[0015] In the formula, R is the radius of the semi-cylinder, ρ w Let ρ be the density of the liquid. s The density of the material is that of a semi-cylinder.

[0016] The wave generation similarity relationship of the hypergravity field is determined based on the dimensionless expression of the wave height of the hypergravity field.

[0017] Optionally, the dimensionless term includes:

[0018] Device amplitude to liquid depth ratio:

[0019]

[0020] Frequency is a dimensionless quantity.

[0021]

[0022] Device radius to liquid depth ratio:

[0023]

[0024] The density ratio of the device to the water density:

[0025]

[0026] Optionally, the scaling factors and corresponding values ​​of each physical quantity in the hypergravity wave simulation are determined based on the dimensionless expression for the hypergravity wave height.

[0027] Optionally, the scaling factors and corresponding values ​​of each physical quantity in the hypergravity field wave simulation are shown in the table below:

[0028]

[0029] Optionally, the similarity rate verification of the hypergravity field wave generation similarity relationship between the predetermined dimensionless quantities of wave height and frequency includes:

[0030] Based on the pre-obtained hypergravity field gravity wave generator, a series of wave generation verification tests were conducted under the same conditions.

[0031] Based on the wave generation verification test, the scaling factors and corresponding values ​​of each physical quantity in the wave generation verification test were obtained.

[0032] Based on the scaling factors and corresponding values ​​of each physical quantity in the wave generation verification test and the scaling factors and corresponding values ​​of each physical quantity in the hypergravity field wave simulation, the similarity rate of the hypergravity field wave generation similarity relationship is verified.

[0033] Optionally, the parameters for calibrating the similarity relationship of the hypergravity field wave generation, provided that the similarity rate verification is consistent, include:

[0034] Under the condition that the similarity rate verification is consistent, wave calibration tests are carried out under different scale conditions according to the hypergravity field gravity wave generator.

[0035] Based on the data obtained from the wave-making similarity relationship in the hypergravity field and the wave-making calibration experiment, the parameters of the wave-making similarity relationship in the hypergravity field are calibrated.

[0036] Optionally, the hypergravity field wave simulation method further includes:

[0037] The pre-obtained hypergravity field gravity wave generator is installed in a centrifuge to construct a hypergravity field.

[0038] This invention can accurately simulate waves in different environments under hypergravity, accurately construct transfer functions, and accurately evaluate the effects of physical quantities such as different motion amplitudes, frequencies, and gravitational accelerations on wave generation. Attached Figure Description

[0039] Figure 1 A flowchart of the hypergravity field wave simulation method provided in the embodiments of the present invention;

[0040] Figure 2 A detailed flowchart of the hypergravity field wave simulation method provided in the embodiments of the present invention;

[0041] Figure 3 This is a schematic diagram of the structure of the gravity wave generator in a hypergravity field provided in an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of a centrifuge provided in an embodiment of the present invention;

[0043] Figure 5 , Figure 6 , Figure 7 This is a schematic diagram of parameter calibration provided in an embodiment of the present invention;

[0044] Figure 8 A flowchart of a simulation experiment provided for an embodiment of the present invention. Detailed Implementation

[0045] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0046] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0047] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0048] Example 1

[0049] This invention provides a method for simulating waves in a hypergravity field, such as... Figure 1 As shown, wave simulation methods in hypergravity fields include:

[0050] S101, Under hypergravity, verify the similarity rate of the hypergravity wave generation similarity relationship between the predetermined dimensionless quantities of wave height and frequency;

[0051] S102, if the similarity rate verification is consistent, calibrate the parameters of the similarity relationship of the supergravity field wave generation;

[0052] S103, based on the similarity relationship of wave generation in the hypergravity field with the calibration parameters, performs hypergravity field wave simulation.

[0053] This invention, through verification of the similarity rate between predetermined dimensionless quantities of wave height and frequency in a hypergravity field, calibrates the parameters of the hypergravity wave similarity relationship when the similarity rate verification is consistent. Based on the calibrated parameters, waves in different environments under a hypergravity field can be accurately simulated, transfer functions can be accurately constructed, and the influence of physical quantities such as different motion amplitudes, frequencies, and gravitational accelerations on wave generation can be accurately assessed.

[0054] In this embodiment of the invention, a pre-obtained hypergravity field gravity wave generator can be installed in a centrifuge to construct a hypergravity field. The hypergravity field gravity wave generator can be obtained through pre-development.

[0055] like Figure 2 As shown, the embodiments of the present invention will be described in detail below through device development and wave simulation.

[0056] I. Device Development Process

[0057] 1. Basic unit comparison

[0058] (1) Device structure:

[0059] In some implementations, the provided hypergravity field gravity wave generator is simply referred to as the device, such as... Figure 3 As shown, it includes a model box, a wave-generating unit, a wave-dissipating unit, and a measurement unit.

[0060] The wave-generating unit includes a power mechanism, a motion mechanism, connecting components, and guide rails. The power mechanism, comprising a hydraulic cylinder and a servo valve, provides power for wave generation. The motion mechanism directly acts on the liquid (water) in the model box to generate waves. The hydraulic cylinder of the power mechanism and the motion mechanism are connected by connecting components, and the motion mechanism is mounted on directional guide rails. Connecting components can be rods. The power mechanism, rods, motion mechanism, and guide rails form a combined transmission structure. This combined transmission structure is installed on one side inside the model box. The motion mechanism is a hollow semi-cylindrical structure, with the length of the semi-cylindrical body matching the width of the model box. The plane of the semi-cylindrical body fits against the side of the model box, and it moves directionally via the guide rails. After the model box is filled with liquid, its equilibrium position is adjusted to the symmetrical axis position of the semi-cylindrical motion mechanism.

[0061] A hydraulic device with a power mechanism drives a hollow semi-cylinder to move up and down periodically. The length of the semi-cylinder is the same as the width of the model box, and the plane of the semi-cylinder is in contact with the side of the model box. It moves up and down in a directional manner through a guide rail, causing the liquid around the semi-cylinder to move along the length of the model box, thereby forming a regular wave load.

[0062] The wave-shrinking unit comprises supports and multiple layers of vertical wave-damping plates. To achieve better wave-damping performance, the vertical wave-damping plates are perforated, with varying porosities across the multiple layers. Specifically, the porosity of the vertical wave-damping plates increases in the direction facing the wave-generating unit. The wave-damping unit is installed on the other side of the model box via supports made of angle steel, which are bolted to the front and rear sides of the model box. The multiple layers of vertical wave-damping plates are fixed to the supports. The wave-damping plates are vertical perforated plates used for passive wave damping; two layers are optional: one is a large-pore vertical wave-damping plate with higher porosity, and the other is a small-pore vertical wave-damping plate with slightly lower porosity. The large-pore vertical wave-damping plate is the first layer, and the small-pore vertical wave-damping plate is the second layer. Porous volcanic rock can be placed between the wave-damping plates to reduce wave and reflected wave energy through the pores, thereby improving the wave-shrinking effect.

[0063] The measurement unit is used to measure the physical parameters of preset wave loads. These parameters include at least wave frequency, wave height, wavelength, and wave velocity. The measurement unit includes a camera component, a wave height meter, and a pore pressure sensor. The camera component includes a top-view camera and a side-view (or main-view) camera. The side-view camera is a high-speed camera used to acquire wave motion data within the model box from the main-view perspective. The high-speed camera is mounted on a support, facing the center of the model box, with its lens pressed against the glass observation window of the model box.

[0064] The camera component, positioned at the top of the model box, acquires wave motion data from a top-down perspective and observes the wave motion within the model box. It is installed on the top of the model box and fixed to the rear wall by brackets and bolts.

[0065] Ultrasonic level gauges and contact level gauges are used to accurately measure and visually display the water level inside the model tank. The wave height gauge is fixed to a crossbeam, which runs along the length of the model tank, with one end of the crossbeam bolted to the tank wall.

[0066] The pore pressure sensor is used to measure the liquid pressure inside the model box and is located at the bottom of the model box.

[0067] A wave height meter and an orifice pressure sensor are used to detect wave motion data at one or more points. Wave motion data from a single point is used to determine wave height and frequency, while data from multiple points is used to determine wavelength and velocity. A camera unit is used to acquire image data of the wave load, which is then used to determine wave frequency, wave height, wavelength, and wave velocity. The data from the wave height meter, orifice pressure sensor, and camera unit are cross-calibrated to ensure accurate parameter determination. The physical parameters of the wave load may also include the device's motion frequency and velocity, which can be obtained from the displacement and maximum thrust curves of the moving mechanism.

[0068] This invention, through reasonable arrangement and structural design, achieves the connection between the wave-generating unit, the clipping unit, the measurement unit, and the model box. For example... Figure 4 As shown, installing the device on a centrifuge rotor can create a hypergravity field.

[0069] (2) Device selection

[0070] Because the semi-cylinder experiences significant buoyancy in water, it can counteract most of its own weight. The hydraulic system moves the semi-cylinder up and down around its equilibrium position, thus generating periodic wave loads. When the hollowness ratio of the semi-cylinder (defined as the ratio of voids to the total volume) is as follows, the equilibrium position is precisely located at the axis of symmetry of the semi-cylinder.

[0071]

[0072] Where, ρ w Let ρ be the density of the liquid. s Let F be the material density of the semi-cylinder. At this point, the maximum thrust F and the stroke of the semi-cylinder satisfy the following condition:

[0073]

[0074] Where F is the maximum thrust, Δh is the maximum displacement of the semi-cylinder, W is the width of the model box, R is the radius of the semi-cylinder, and ng is the centrifugal acceleration. The device can be set up on a centrifuge to conduct wave generation tests.

[0075] The formula shows that the maximum thrust is related to the volume of the motion mechanism. For wedge-shaped and semi-cylindrical motion mechanisms with the same cross-sectional width and height, the semi-cylindrical motion mechanism can generate greater thrust and generate a larger wave height under the same stroke. The curved surface design reduces water flow separation and has higher energy transfer efficiency. The waves generated by the semi-cylindrical mechanism are smoother, have fewer secondary reflections, have strong nonlinear characteristics, and the waveform is closer to natural waves. It is more suitable for centrifugal tests and can generate multi-directional waves.

[0076] Within an effective controllable range, different wave loads can be generated by adjusting the thrust, frequency, and centrifugal acceleration. Under hypergravity, since both the Mach number and Froude number satisfy a similarity relationship, the obtained wave load attenuation law, as well as the interaction between underwater explosive loads and wave loads under wave conditions, will be similar to the prototype.

[0077] 2. Model assembly

[0078] Based on the basic units identified above, the model is assembled.

[0079] 3. Wave test

[0080] Based on the wave-making test data, the selection of basic units was revised.

[0081] II. Wave Generation Test in a Supergravity Field

[0082] 1. Confirmation of relevant physical quantities

[0083] Typically, wave height H and frequency f are... w Physical quantities such as wavelength λ and wave speed v are all related to the following variables:

[0084] Wave-generating parameters: device amplitude S, device motion frequency f0, semi-cylinder radius R, device density ρ s ;

[0085] Environmental parameters: liquid depth h, liquid density ρ w ;

[0086] Hypergravity parameters: gravitational acceleration ng,

[0087] The expression for wave height H is:

[0088] H=f(S,f0,r,h,ρ w ,ρ s ,ng)

[0089] Wave height, wave height, and wave height all refer to the height of the wave.

[0090] 2. Dimensional analysis to determine the similarity relationship of wave generation in a hypergravity field.

[0091] Based on dimensional analysis, the liquid density ρ is selected. w With gravitational acceleration ng and water depth h as repeated variables, construct a dimensionless Π term:

[0092] Device amplitude to liquid depth ratio:

[0093]

[0094] Frequency is a dimensionless quantity.

[0095]

[0096] Ratio of semi-cylinder radius to liquid depth:

[0097]

[0098] The density ratio of the device to the water density:

[0099]

[0100] Establish a dimensionless expression for wave height in a hypergravity field.

[0101]

[0102] Based on this formula, the scaling factors of each physical quantity in the simulation of hypergravity wave field can be obtained.

[0103] Table 1. Scale Factors of Hypergravity Field

[0104]

[0105]

[0106] For a specific liquid and a specific moving mechanism, π3 and π4 remain constant. The amplitude of the device is much smaller than the water depth, therefore π1 changes little and has a negligible impact on wave height. Thus, the generated wave height is mainly related to π2. The above equation simplifies to...

[0107]

[0108] 3. Similarity verification, i.e., verification of wave similarity in hypergravity fields.

[0109] To ensure the reliability of the experiment, the wave simulation similarity can be verified using the following methods: For the prototype, experiments are conducted at different scales, with water depth, device size, and motion frequency adjusted according to the device similarity relationship. This verifies the wave height similarity at the prototype scale. Simultaneously, experiments can be conducted on land to verify the influence of the hypergravity field on the wave simulation.

[0110] (1) Calibration of transfer function

[0111] First, a similarity rate verification study is conducted on the wave height. This involves carrying out a series of experiments under identical conditions to determine whether the experiments can revert to the same results. If the results are consistent, it will directly prove the validity of the similarity relationship in the table above. For example, based on a gravity-type wave generator in a hypergravity field, a series of wave generation verification experiments are conducted under the same conditions. Based on the wave generation verification experiments, the scaling factors and corresponding values ​​of each physical quantity in the wave generation verification experiments are obtained. Based on the scaling factors and corresponding values ​​of each physical quantity in the wave generation verification experiments and the scaling factors and corresponding values ​​of each physical quantity in the hypergravity field wave simulation, the similarity rate verification of the hypergravity field wave generation similarity relationship is performed. If the results are consistent, it will directly prove the validity of the similarity relationship in the table above.

[0112] (2) Determine the formula parameters and confirm the transfer function

[0113] After verifying the correlation between wave height parameters and [the relationship between wave height and wave parameters], experiments were conducted under different conditions, such as... Figure 5 As shown, the functional relationship between wave height and wave rate is obtained, and the parameters are calibrated. For example, under the condition that the similarity rate verification is consistent, wave generation calibration tests are carried out under different scales according to the hypergravity field gravity wave generation device; based on the hypergravity field wave generation similarity relationship and the data obtained from the wave generation calibration test, the parameters of the hypergravity field wave generation similarity relationship are calibrated.

[0114] 4. Wave generation experiment in a supergravity field

[0115] The process includes designing an experimental scheme, constructing a model of the gravity-based wave generator in a hypergravity field, installing equipment such as centrifuges, conducting ground tests, inspecting the equipment, and adjusting parameters based on the results. If the desired outcome is achieved, core calculations, cable connections, oil circuit connections, counterweight adjustment, hypergravity testing, and completion of the experiment are performed. The experimental model can be constructed according to the experimental scheme, and the device can be protected and waterproofed. The effects of different motion amplitudes, frequencies, and gravitational accelerations on wave generation can be studied, and expressions for wave elements can be established based on similarity theory. For frequencies with partial resonance that cannot form stable waveforms, the gravitational acceleration can be adjusted, and the simulated frequency can be changed. For stable waveforms, classification and identification are performed, and transfer functions are constructed. Based on the stability of wave generation, further explosion tests can be added to simulate the impact of waves on explosive load sequences in a marine environment.

[0116] The hypergravity field wave simulation method of this invention has achieved significant results in many aspects. It can accurately simulate waves in different environments under hypergravity, accurately construct transfer functions, and accurately evaluate the influence of physical quantities such as different motion amplitudes, different frequencies, and different gravitational accelerations on wave generation.

[0117] Although the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. Various adjustments or changes may be made to the exemplary embodiments described in this specification without departing from the scope or spirit of the invention. The scope of the claims should be interpreted in the broadest possible sense to cover all modifications and equivalent structures and functions.

Claims

1. A method for simulating waves in a hypergravity field, characterized in that, The hypergravity field wave simulation method includes: Based on the dimensionless term, a dimensionless expression for the wave height in the hypergravity field is established; based on the dimensionless expression for the wave height in the hypergravity field, the similarity relationship between the wave height and frequency dimensionless quantities in the hypergravity field wave simulation, as well as the scaling factors and corresponding values ​​of each physical quantity in the hypergravity field wave simulation, are determined. Under hypergravity, the similarity rate of the hypergravity wave generation similarity relationship between predetermined dimensionless quantities of wave height and frequency is verified. Specifically, this includes: conducting a series of wave generation verification tests under the same conditions using a pre-obtained hypergravity gravity wave generation device; obtaining the scaling factors and corresponding values ​​of each physical quantity in the wave generation verification tests; and verifying the similarity rate of the hypergravity wave generation similarity relationship based on the scaling factors and corresponding values ​​of each physical quantity in the wave generation verification tests and the scaling factors and corresponding values ​​of each physical quantity in the hypergravity wave simulation. Under the condition that the similarity rate verification is consistent, the parameters of the similarity relationship of the supergravity field wave generation are calibrated; specifically, under the condition that the similarity rate verification is consistent, wave generation calibration tests are conducted on the supergravity field gravity wave generation device under different scale conditions; based on the data obtained from the supergravity field wave generation similarity relationship and the wave generation calibration test, the parameters of the supergravity field wave generation similarity relationship are calibrated. Based on the similarity relationship of wave generation in the hypergravity field with the calibration parameters, a hypergravity field wave simulation is performed. The dimensionless terms include: Device amplitude to liquid depth ratio: Frequency is a dimensionless quantity. Device radius to liquid depth ratio: The ratio of material density to liquid density in the device: The dimensionless expression for the height of the hypergravity field wave is: In the formula, r For the radius of the device, ρ w For the density of the liquid, ρ s The density of the material in the device, S The amplitude of the device; Based on the generation wave height mainly related to Therefore, the above equation simplifies to obtain the similarity relationship of the supergravity field wave generation as follows: In the formula, H For wave height, h The depth of the liquid in the device. The frequency of the device's movement. S For device amplitude, This is the acceleration due to gravity.

2. The method for simulating waves in a hypergravity field according to claim 1, characterized in that, The scaling factors and corresponding values ​​of various physical quantities in the hypergravity field wave simulation are shown in the table below: 。 3. The method for simulating waves in a hypergravity field according to claim 1, characterized in that, The hypergravity field wave simulation method also includes: The pre-obtained hypergravity field gravity wave generator is installed in a centrifuge to construct a hypergravity field.

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