A design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas

Abstract

This invention proposes a design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas. First, data collection and processing are performed, collecting and processing relevant information about the target sea area and sea ice. Then, based on the potential flow theory model, the wave generation period interval, sea ice strain response, wave height scaling factor are calculated. The wave height scaling factor is used to calculate the target wave height and maximum stroke, resulting in the target period wave. Finally, the target period wave is used to obtain the wave generator shape curve, completing the wave generator design.

Description

Technical Field

[0001] This invention belongs to the field of marine technology in ice-covered areas, specifically, it relates to a design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas. Background Technology

[0002] Since the 20th century, various types of drilling and production platforms have been put into service in polar regions worldwide. Predicting the overall and local ice loads on offshore platform structures in cold regions is a crucial step in assessing the ice resistance and ice-induced fatigue of offshore engineering structures in these regions. Previously, the design of offshore platforms in polar regions often involved adding ice-resistant structures such as ice cones to improve operational safety and stability. However, when an offshore platform collides with sea ice, especially when the excitation frequency of the collision between the platform and sea ice of different types and sizes is close to the platform's natural frequency due to ice accumulation or other reasons, unassessed coupled resonance can easily occur, threatening the platform's structural safety.

[0003] Currently, strengthening local structures is not the most effective way to ensure safety. Instead, proactively breaking or removing sea ice through external means can reduce the impact of sea ice on structures at its source, thereby minimizing the interaction between the offshore platform and sea ice and providing better safety and stability. However, effective icebreaking or ice removal methods are currently limited, representing a pressing problem to be solved in the field of ice-covered marine engineering. Summary of the Invention

[0004] To mitigate the impact of sea ice on marine structures, this invention proposes a design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas. This method enables the design of an effective and feasible omnidirectional icebreaker wave generator that achieves icebreaking and ice removal in the target sea area, providing a new solution and design method for the safety of marine structures in ice-covered areas.

[0005] This invention is achieved through the following technical solution:

[0006] A design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas:

[0007] The method specifically includes the following steps:

[0008] Step 1, Data Collection and Processing: Collect and process relevant information about the target sea area and sea ice.

[0009] Step 2: Obtain the wave generation period interval based on the data processed in Step 1:

[0010] Step 3: Calculate the sea ice strain response based on the wave generation period interval obtained in Step 2:

[0011] Step 4: Calculate the wave height scaling factor based on the sea ice strain response obtained in Step 3.

[0012] Step 5: Calculate the target wave height and maximum stroke based on the wave height scaling factor obtained in Step 4 to obtain the target periodic wave:

[0013] Step 6: Obtain the wave generator shape curve based on the target period wave obtained in Step 5, and complete the wave generator design.

[0014] Furthermore, in step 1,

[0015] The data collection involves acquiring information about the target sea area and sea ice, including the depth of the sea area, the thickness of the sea ice, the mechanical properties of the sea ice, and the size of the sea ice surface area.

[0016] The sea area information and sea ice information data are processed, and the thickest and largest sea ice is selected for design calculation. The processed data is then substituted into the theoretical model of the interaction between waves and sea ice derived from potential flow theory, and the incident wave height is taken as the unit wave height.

[0017] Furthermore, in step 2,

[0018] Based on the wave transmission coefficient calculated from the potential flow theory model of the interaction between waves and sea ice, the period range of wave generation motion is selected accordingly. The selected range should be a transmission coefficient of 0.8 to 1.0.

[0019] Furthermore, in step 3,

[0020] Using the potential flow theory model, the period interval selected in step 2 was substituted into the calculation, and the distance between the wave source and the sea ice was selected to calculate the strain response of the sea ice under the action of waves of different periods at that distance.

[0021] Furthermore, in step 4,

[0022] Based on the sea ice strain obtained in step 3, the wave height scaling factor a is calculated using the following formula:

[0023]

[0024] Where ε max ε is the maximum strain value of sea ice. critical The critical strain value corresponding to sea ice fracturing is an empirical value, generally ranging from 2 to 8 × 10⁻⁶. -5 .

[0025] Furthermore, in step 5,

[0026] Multiply the wave height obtained in step 1 by the wave height scaling factor a calculated in step 4 to obtain the target wave height H required for icebreaking under the selected wave cycle.

[0027] Calculate the maximum stroke of the wave generator based on the target wave height H. The calculation formula is as follows:

[0028]

[0029] Where k is the wave number and h is the water depth.

[0030] Furthermore, in step 6,

[0031] Calculate the wave speed based on the wave of the target period:

[0032]

[0033] Where g is the acceleration due to gravity and T is the period of the wave.

[0034] A wave generator typically undergoes simple harmonic motion. If the vertical velocity of the wave generator is given as V... y .

[0035] Assuming the water surface is still, the rate of change of the waterline on the horizontal surface is:

[0036] V x =V y ×F′(x)

[0037] To ensure effective wave stacking during wave generation, V x The average value of a single stroke must be greater than or equal to the wave speed v, but not exceed 1.1v.

[0038] A design system for an omnidirectional icebreaking wave generator in actual ice-covered sea areas:

[0039] The system includes a data acquisition module, a calculation module based on a potential flow theory model, and a wave generator design module.

[0040] The data acquisition module is used for data collection and processing, collecting and processing relevant information about the target sea area and sea ice;

[0041] The calculation module based on the potential flow theory model is used to obtain the wave generation period interval, sea ice strain response, wave height scaling factor, and to calculate the target wave height and maximum stroke using the wave height scaling factor, ultimately obtaining the target period wave:

[0042] The wave generator design module obtains the wave generator shape curve based on the target period wave obtained by the calculation module based on the potential flow theory model, and completes the wave generator design.

[0043] An electronic device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the above method.

[0044] A computer-readable storage medium for storing computer instructions that, when executed by a processor, implement the steps of the above-described method.

[0045] Beneficial effects of the invention

[0046] This invention allows for customized design based on the specific conditions of the target sea area, including sea ice characteristics and sea depth. It is more flexible than general design methods and can better adapt to different environmental conditions.

[0047] The method of this invention emphasizes selecting the thickest and largest sea ice for design calculations to ensure that engineering safety requirements are met even under the most unfavorable conditions. Utilizing potential flow theory models to calculate the interaction between waves and sea ice provides more accurate analysis and predictions.

[0048] This invention ensures that wave energy can be effectively applied to the ice layer by calculating the wave transmission coefficient and wave energy transfer, thereby improving icebreaking efficiency and reducing energy waste. Furthermore, it calculates parameters such as wave height scaling factor and maximum stroke. These parameterized design methods make it easier to adjust and optimize the performance of the wave generator.

[0049] Because this invention utilizes marine information data, the method possesses a certain degree of real-time adaptability, allowing adjustments to be made based on different seasons or specific marine conditions to cope with constantly changing environments. Attached Figure Description

[0050] Figure 1 This is a top view of the schematic diagram of the wave-generating device and its interaction with sea ice shown in this invention, where 1 is the omnidirectional wave-generating device, 2 is sea ice, and the surrounding blank area is fluid.

[0051] Figure 2 This is a front view of the schematic diagram of wave generation and sea ice interaction shown in this invention, where 1 is an omnidirectional wave generation device, 2 is sea ice, and fluid is below the device and sea ice.

[0052] Figure 3 It is a curve function representing the half-section shape of the wave generator;

[0053] Figure 4 This is an example diagram showing the distribution of transmission coefficient as a function of wave period;

[0054] Figure 5 This is an example diagram showing the calculation of sea ice strain distribution; Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] The potential flow theory model is based on the following fundamental assumptions:

[0057] Fluids are incompressible, meaning their density remains constant.

[0058] The velocity field of a fluid is irrotational, which means that fluid particles do not rotate around a closed trajectory.

[0059] The potential energy function (potential flow function) can be used to describe the flow field, and it satisfies the Laplace equation.

[0060] In the design of omnidirectional icebreaker wave generators, the potential flow theory model is mainly used in the following aspects:

[0061] Wave propagation and refraction: Potential flow theory models can be used to describe how waves propagate on sea ice, including variations in wave speed, wavelength, and wave height. This helps in understanding how waves reflect and refract on sea ice, and the energy distribution of waves under different conditions.

[0062] Wave-sea-ice interaction: Potential flow theory models can help calculate the interaction between waves and sea ice, including the forces exerted by waves on sea ice and the sea ice's response to waves. This is crucial for determining the wave energy required during icebreaking.

[0063] Calculation of wave transmission coefficient: When designing a wave generator, it is necessary to calculate the wave transmission coefficient to determine the appropriate wave period range. This coefficient is part of the potential flow theory model, and it tells us the extent to which waves are transmitted after interacting with sea ice.

[0064] Wave energy transfer: Using potential flow theory models, we can calculate how wave energy is transferred to sea ice under different wave cycles to ensure sufficient energy transfer for icebreaking.

[0065] Combination Figure 1 and Figure 5 ;

[0066] Figure 1 The wave-generating device generates waves by propelling the fluid below it through the swaying motion of the free surface, thus creating waves that spread outwards.

[0067] Figure 2The diagram shows the bending deformation of sea ice caused by the bending gravity waves after the waves generated by the wave generator enter the sea ice.

[0068] A design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas:

[0069] The method specifically includes the following steps:

[0070] Step 1, Data Collection and Processing: Collect and process relevant information about the target sea area and sea ice.

[0071] The data collection involves acquiring information about the target sea area and sea ice, including the depth of the sea area (seawater depth affects wave propagation and interaction), the type of ice (multi-year ice, annual ice, broken ice, etc.), the distribution, density, thickness, mechanical properties (e.g., yield strength and fracture characteristics) and surface area of ​​the sea ice.

[0072] It also includes geographical and meteorological data for the target ice zone, such as longitude, latitude, seasonal variations, as well as temperature and weather conditions;

[0073] In the embodiments, according to published literature, the average water depth of the Bohai Sea is 18m, the maximum water depth is 85m, the area of ​​the sea with a depth of less than 20m accounts for more than half, the annual sea ice thickness is generally 0.2 to 0.3m, the elastic modulus of the sea ice is 1 to 5GPa, and the Poisson's ratio is 0.3.

[0074] The sea area and sea ice information data are processed, and the thickest and largest sea ice is selected for design calculations to ensure that the design is based on the worst-case scenario to meet the safety requirements of the project. The processed data is then substituted into a theoretical model of wave-sea ice interaction derived from potential flow theory, using the incident wave height as the unit wave height. Potential flow theory helps determine the wave propagation mode and their interaction with the ice layer.

[0075] Based on the collected data, a sea ice model with a target water depth of 20m and an ice-breaking thickness of 0.4m was designed, with the sea ice elastic modulus taken as 5 GPa. The data was then substituted into a theoretical model of wave-sea ice interaction to calculate the transmission coefficient distribution as a function of wave period. For example... Figure 4 As shown.

[0076] Step 2: Obtain the wave generation period interval based on the data processed in Step 1:

[0077] Based on the wave transmission coefficient calculated from the potential flow theory model of the interaction between waves and sea ice, the period range of wave generation is selected accordingly. The selected range should be a transmission coefficient of 0.8 to 1.0, so that the energy of the waves can be more effectively applied to the ice layer.

[0078] In this embodiment, based on the transmission coefficient distribution map calculated in the previous step, a wave with a period of 8 seconds is selected, and the transmission coefficient can reach more than 0.9. Theoretically, the wave can effectively act on the ice layer.

[0079] The wave transmission coefficient, calculated using a potential flow theory model, is an indicator of the effectiveness of wave transmission to the ice layer. A transmission coefficient between 0.8 and 1.0 is selected to ensure that waves can effectively act on the ice layer.

[0080] The period range of the wave-generating motion is selected to ensure that sufficient wave energy is transferred to the ice layer under different conditions. This depends on the characteristics of the sea ice and the desired effect.

[0081] Step 3: Calculate the sea ice strain response based on the wave generation period interval obtained in Step 2:

[0082] The potential flow theory model (a theoretical model of the interaction between waves and sea ice) is used to calculate the strain response of sea ice under the action of waves of different periods at this distance. The period interval selected in step 2 is substituted into the model, and the distance between the wave source and the sea ice is selected as 20m. This distance is not fixed and can be adjusted according to the needs.

[0083] Step 4: Calculate the wave height scaling factor based on the sea ice strain response obtained in Step 3: (e.g.) Figure 5 ;

[0084] Based on the sea ice strain obtained in step 3, the wave height scaling factor a is calculated using the following formula:

[0085]

[0086] Where ε max ε represents the maximum strain value of sea ice calculated in step 3. critical The critical strain value corresponding to sea ice fracturing is an empirical value, generally ranging from 2 to 8 × 10⁻⁶. -5 .

[0087] In this embodiment, the critical strain value is taken as 8 × 10⁻⁶. -5 Substituting the parameters obtained in the previous step into the wave height scaling factor formula, we get the scaling factor as follows:

[0088]

[0089] Step 5: Calculate the target wave height and maximum stroke based on the wave height scaling factor obtained in Step 4 to obtain the target periodic wave:

[0090] Multiply the wave height obtained in step 1 by the wave height scaling factor a calculated in step 4 to obtain the target wave height H required for icebreaking under the selected wave cycle.

[0091] Calculate the maximum stroke of the wave generator based on the target wave height H. The calculation formula is as follows:

[0092]

[0093] Where k is the wave number and h is the water depth.

[0094] In this embodiment, the calculation uses a unit wave height of 1m. The wave height is multiplied by the wave height scaling factor a mentioned in the previous step to obtain the target wave height required for icebreaking under the selected wave cycle: H = 1 × a = 1.71m.

[0095] Based on the target wave height H described in the previous step, the maximum stroke of the wave generator is calculated as follows:

[0096]

[0097] Step 6: Obtain the wave generator shape curve based on the target period wave obtained in Step 5, and complete the wave generator design.

[0098] Calculate the wave speed based on the wave of the target period:

[0099]

[0100] Where g is the acceleration due to gravity and T is the period of the wave.

[0101] The shape of the wave generator should conform to a streamlined shape as much as possible, such as a wedge or a sphere. The curve function F(x) of the half-section shape of the wave generator should be taken, such as... Figure 3 As shown:

[0102] A wave generator typically undergoes simple harmonic motion. If the vertical velocity of the wave generator is given as V... y .

[0103] Assuming the water surface is still, the lateral rate of change of the waterline on the horizontal surface is:

[0104] V x =V y ×F′(x)

[0105] To ensure effective wave stacking during wave generation, V x The average value of a single stroke must be greater than or equal to the wave speed v, but not exceed 1.1v.

[0106] For a wedge-shaped wave generator, the average velocity can be directly calculated using the following formula:

[0107]

[0108] Where λ is the slope of the shape.

[0109] Wavemaker shape curve: Taking the cross-sectional shape of the wavemaker as wedge-shaped, the average velocity of the waterline's lateral change is:

[0110]

[0111] Based on the wave velocity v of the target period, which is approximately 12.478 m / s, the slope λ of the wave generator shape is 19.436, resulting in a radius of 24.956 m, which is rounded to 25 m. The height of the wave generator only needs to be greater than the maximum stroke, so we take 1.5 m.

[0112] Therefore, the wave generator is a wedge-shaped cone with a height of 1.5m and a radius of 25m.

[0113] A design system for an omnidirectional icebreaking wave generator in actual ice-covered sea areas:

[0114] The system includes a data acquisition module, a calculation module based on a potential flow theory model, and a wave generator design module.

[0115] The data acquisition module is used for data collection and processing, collecting and processing relevant information about the target sea area and sea ice;

[0116] The calculation module based on the potential flow theory model is used to obtain the wave generation period interval, sea ice strain response, wave height scaling factor, and to calculate the target wave height and maximum stroke using the wave height scaling factor, ultimately obtaining the target period wave:

[0117] The wave generator design module obtains the wave generator shape curve based on the target period wave obtained by the calculation module based on the potential flow theory model, and completes the wave generator design.

[0118] An electronic device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of the above method.

[0119] A computer-readable storage medium for storing computer instructions that, when executed by a processor, implement the steps of the above-described method.

[0120] The memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDR SDRAM), enhanced synchronous DRAM (ESDRAM), synchronous linked DRAM (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory of the methods described in this invention is intended to include, but is not limited to, these and any other suitable types of memory.

[0121] The above provides a detailed description of the design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas proposed by the present invention, and elucidates the principle and implementation of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A design method for an omnidirectional icebreaker wave generator in actual ice-covered sea areas, characterized in that: The method specifically includes the following steps: Step 1, Data Collection and Processing: Collect and process relevant information about the target sea area and sea ice. The data collection involves acquiring information about the target sea area and sea ice, including the depth of the sea area, the thickness of the sea ice, the mechanical properties of the sea ice, and the size of the sea ice surface area. The sea area information and sea ice information data are processed, the thickest and largest sea ice is selected for design calculation, and the processed data is substituted into the theoretical model of wave and sea ice interaction derived from potential flow theory, with the incident wave height taken as the unit wave height. Step 2: Obtain the wave generation period interval based on the data processed in Step 1; Step 3: Calculate the sea ice strain response based on the wave generation period interval obtained in Step 2; Based on the sea ice strain obtained in step 3, calculate the wave height scaling factor. a The calculation formula is as follows: in This represents the maximum strain value of sea ice. The critical strain value corresponding to sea ice fracturing is an empirical value, taken as... ; Step 4: Calculate the wave height scaling factor based on the sea ice strain response obtained in Step 3; Step 5: Calculate the target wave height and maximum stroke based on the wave height scaling factor obtained in Step 4 to obtain the target periodic wave. Multiply the wave height obtained in step 1 by the wave height scaling factor calculated in step 4. a The target wave height required for icebreaking under the selected wave period is obtained. Size; Based on the target wave height Calculate the maximum stroke of the wave generator; the calculation formula is as follows: in For wave number, For water depth; Step 6: Obtain the wave generator shape curve based on the target period wave obtained in Step 5, and complete the wave generator design.

2. The method according to claim 1, characterized in that: In step 2, Based on the wave transmission coefficient calculated from the potential flow theory model of the interaction between waves and sea ice, the period range of wave generation is selected accordingly. The selected range should be a transmission coefficient of 0.8 to 1.

0.

3. The method according to claim 2, characterized in that: In step 3, Using the potential flow theory model, the period interval selected in step 2 was substituted into the calculation, and the distance between the wave source and the sea ice was selected to calculate the strain response of the sea ice under the action of waves of different periods at that distance.

4. The method according to claim 3, characterized in that: In step 6, Calculate the wave speed based on the wave of the target period: in It is the acceleration due to gravity. The period of the wave; The wave generator is undergoing simple harmonic motion. Given the vertical velocity of the wave generator as... ; Assuming the water surface is still, the rate of change of the waterline on the horizontal surface is: To ensure effective wave stacking during wave generation, The average value of a single stroke is greater than or equal to the wave speed. However, it does not exceed 1.1 .

5. A design system for an omnidirectional icebreaking wave generator in actual ice-covered sea areas, characterized in that: The system is based on the design method of an omnidirectional icebreaker wave generator in actual ice-covered sea areas as described in any one of claims 1 to 4; The system includes a data acquisition module, a calculation module based on a potential flow theory model, and a wave generator design module. The data acquisition module is used for data collection and processing, collecting and processing relevant information about the target sea area and sea ice; The data collection involves acquiring information about the target sea area and sea ice, including the depth of the sea area, the thickness of the sea ice, the mechanical properties of the sea ice, and the size of the sea ice surface area. The sea area information and sea ice information data are processed, the thickest and largest sea ice is selected for design calculation, and the processed data is substituted into the theoretical model of wave and sea ice interaction derived from potential flow theory, with the incident wave height taken as the unit wave height. The calculation module based on the potential flow theory model is used to obtain the wave generation period interval, sea ice strain response, wave height scaling factor, and to calculate the target wave height and maximum stroke using the wave height scaling factor, ultimately obtaining the target period wave: Calculate the wave height scaling factor based on the obtained sea ice strain information. a The calculation formula is as follows: in This represents the maximum strain value of sea ice. The critical strain value corresponding to sea ice fracturing is an empirical value, taken as... ; Multiply the wave height by the wave height scaling factor. a The target wave height required for icebreaking under the selected wave period is obtained. Size; Based on the target wave height Calculate the maximum stroke of the wave generator; the calculation formula is as follows: in For wave number, For water depth; The wave generator design module obtains the wave generator shape curve based on the target period wave obtained by the calculation module based on the potential flow theory model, and completes the wave generator design.

6. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 4.

7. A computer-readable storage medium for storing computer instructions, characterized in that, When the computer instructions are executed by the processor, they implement the steps of the method according to any one of claims 1 to 4.

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