An experimental device for studying extreme wave overtopping and scour evolution of reef breakwater

Abstract

The application discloses an experimental device for researching extreme wave overtopping and scour evolution of an island reef breakwater, comprising a wave experiment water tank, a reef front slope model, a reef flat model, a reef rear slope model, a breakwater model, an overtopping measuring device and a scour topography measuring device. The experimental device obtains the deformation characteristics of extreme waves along the way by arranging a wave height instrument on the island reef model; the distribution of extreme wave slamming pressure along the surface of the breakwater is measured by installing a pressure sensor in the breakwater model; the process of extreme wave slamming, overtopping and scouring of the island reef breakwater is obtained in real time by arranging a high-speed camera; the overtopping amount of the breakwater is measured by using the overtopping measuring device; and the island reef scour topography is obtained by using a laser topography scanner. The experimental device can realize experimental research on the process of extreme wave overtopping and scouring of the island reef breakwater under different wave heights, wave periods, water depths, reef front slope gradients, reef flat lengths and breakwater positions.

Description

Technical Field

[0001] This invention relates to an experimental apparatus for studying the extreme wave impact, overtopping, and scouring evolution of island and reef breakwaters, particularly for studying the impact, overtopping, and scouring evolution of island and reef breakwaters under different wave heights, wave periods, water depths, slopes of the foreshore slope, lengths of the reef flat, slopes of the aft slope, and breakwater locations. Background Technology

[0002] Currently, research on wave propagation at island and reef breakwaters mainly employs two methods: numerical simulation and physical model experiments. Numerical simulation, however, is computationally intensive for the breaking process on island and reef topography and cannot accurately simulate the air entrainment phenomenon during wave breaking. Compared to numerical simulation, physical model experiments can more realistically reflect the extreme wave impact, overtopping, and scouring evolution processes of island and reef breakwaters. Current physical experiments on island and reef breakwaters primarily study the hydrodynamic processes of waves on breakwaters with island and reef topography, but few experiments focus on the scouring process of breakwaters on island and reef topography. Physical model experimental setups for studying the changes in scouring characteristics of island and reef breakwaters under different influencing factors are still lacking. Summary of the Invention

[0003] Traditional breakwater physical model experimental devices can only study hydrodynamic or scour-related issues independently, without considering the influence of island and reef topography on the impact, overtopping, and scour of breakwaters by extreme waves. This invention designs an experimental device to study the evolution of overtopping, slamming, and scour processes of island and reef breakwaters caused by extreme waves. This experimental device can measure the wave height distribution along the island and reef topography, the wave slamming pressure distribution along the breakwater surface, the wave slamming load, the overtopping amount, and the island and reef scour topography. It elucidates the evolution of the impact, overtopping, and scour processes of island and reef breakwaters under different wave heights, wave periods, water depths, foreshore slope gradients, reef flat lengths, aftshore slope gradients, and breakwater locations.

[0004] The technical solution adopted in this invention is:

[0005] An experimental apparatus for studying the impact, overtopping, and scouring evolution of extreme waves on island and reef breakwaters is characterized by comprising an experimental water tank, a reef-front slope model, a reef flat model, a reef-back slope model, a breakwater model, an overtopping measurement device, and a scouring topography measurement device fixed on the water tank frame.

[0006] The aforementioned reef front slope model and reef back slope model include aluminum alloy profiles and stainless steel plates. The aluminum alloy profiles are connected to each other through profile connecting corner pieces to form a frame, and the stainless steel plates are fixed to the upper surface of the frame by T-bolts and nuts.

[0007] The reef flat model includes aluminum alloy profiles and acrylic sheets. The aluminum alloy profiles are connected to each other to form a frame through profile connecting corner pieces. The scouring trough is made of acrylic sheets and fixed to the frame with T-bolts and nuts. Calcareous sand is laid in the scouring trough.

[0008] The breakwater model is welded from stainless steel plates, and several nuts are pre-drilled on the surface of the breakwater.

[0009] The wave measurement device includes a flow channel, a stainless steel pipe, a stainless steel shell, a water collection tank, a breakwater model, and the stainless steel shell, which are welded together by the stainless steel pipe. One end of the flow channel of the water collection tank is connected to the top of the breakwater model, and the other end is connected to the water collection tank.

[0010] The terrain surveying device includes a slide rail, an aluminum alloy profile, and a terrain scanner. The slide rail is fixed to the water tank frame by bolts and nuts. The aluminum alloy profile is connected to the slider on the slide rail by T-bolts and nuts. The terrain scanner is fixed below the aluminum alloy profile.

[0011] In the above technical solution, the island and reef topography is further composed of a front slope, a reef flat, and a back slope. The front slope and back slope models are made of aluminum alloy profiles and stainless steel plates, and the reef flat model is made of aluminum alloy profiles and acrylic plates to form a scouring trough, which is filled with calcareous sand.

[0012] Furthermore, bolt holes are pre-drilled on the surface of the breakwater model, and pressure sensors are installed in the bolt holes to measure the pressure distribution on the breakwater surface. The water collection tank of the wave overtopping device can collect the water passing through the guide channel on the breakwater model and calculate the wave overtopping on the breakwater.

[0013] Furthermore, the slide rail is fixed on the water tank frame, and the slider is connected to the aluminum alloy profile with the terrain scanner, which can ensure that the terrain scanner moves smoothly along the direction of the water tank.

[0014] This invention also provides an experimental method for studying the impact, overtopping, and scouring evolution of extreme waves on island and reef breakwaters. This method is based on the aforementioned device and includes the following steps:

[0015] First, an empty water tank was filtered in the experimental tank to ensure that waves of the specified height and period were generated by the wave generator. Then, models of the foreshore slope, reef flat, aft slope, and breakwater were arranged in the experimental tank. Waves of different heights and periods were generated using the wave generator, causing propagation deformation in the island and reef terrain. Upon reaching the breakwater model, extreme wave impacts and overtopping occurred, resulting in localized scouring at the breakwater model location. Wave height changes and pressure distribution on the breakwater model were measured using wave height meters and pressure sensors. The wave overtopping amount on the breakwater model was measured using a wave overtopping measurement device; the wave propagation deformation, slamming, overtopping and scouring processes were captured by a high-speed camera, and the images were processed and analyzed using MATLAB to obtain the two-dimensional topographic time history changes during the scouring process; the scouring terrain was scanned by a topographic scanner to obtain the three-dimensional topographic data after scouring; and the wave slamming, overtopping and scouring evolution processes of the island and reef breakwater were studied under different experimental conditions, including different wave heights, wave periods, water depths, reef fore slopes, reef flat lengths, reef abutment slopes, and different breakwater locations.

[0016] The advantages of this invention are:

[0017] This invention enables the study of extreme wave impact, overtopping, and scouring evolution processes of island and reef breakwaters in an experimental water tank. The experimental setup designed in this invention can measure the propagation deformation of wave height along the island / reef topography and the distribution of wave impact pressure along the breakwater surface; measure the overtopping amount of the breakwater using an overtopping measurement device; record the wave impact, overtopping, and scouring evolution processes using a high-speed camera; furthermore, obtain the post-scouring topography using a topographic scanner after the experiment; and, moreover, this invention can achieve experimental research on the extreme wave impact, overtopping, and scouring evolution processes of island and reef breakwaters under different wave heights, wave periods, water depths, foreshore slope gradients, reef flat lengths, aft slope gradients, and breakwater locations. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the construction of the reef-front slope model of the present invention.

[0019] Figure 2 This is a schematic diagram of the reef flat model of the present invention.

[0020] Figure 3 This is a schematic diagram of the construction of the reef back slope model of the present invention.

[0021] Figure 4 This is a schematic diagram of the topographic surveying device of the present invention.

[0022] Figure 5 This is a schematic diagram of the breakwater model and the wave measurement device of the present invention.

[0023] Figure 6 This is a cross-sectional schematic diagram of the breakwater model and the wave overtopping measurement device of the present invention.

[0024] Figure 7 This is a schematic diagram of the entire setup.

[0025] 1. Aluminum alloy profile 2. Profile connecting corner fittings 3. Stainless steel plate 4. T-bolts and nuts 5. Acrylic plate 6. Slide rail 7. Slider 8. Topographic scanner 9. Nut 10. Stainless steel pipe 11. Diversion channel 12. Stainless steel shell 13. Water collection tank 14. Weighing instrument 15. Reef fore slope model 16. Reef flat model 17. Reef aft slope model 18. Breakwater model and overtopping measurement device 19. Topographic surveying device. Detailed Implementation

[0026] The technical solution of the present invention will be further described below, but the scope of protection of the present invention is not limited to the described embodiments.

[0027] An experimental apparatus for studying the evolution of extreme wave impact, overtopping and scouring of breakwaters on islands and reefs includes an experimental tank, a front slope 15, a reef flat 16 and a back slope 17, a breakwater model and an overtopping measurement device 18, and a topographic measurement device 19 fixed on the tank frame.

[0028] like Figure 7 This is a schematic diagram of the entire device of the present invention. The foreshore slope 15, the reef flat 16, and the aft slope 17 are interconnected by T-bolts and nuts 4 and fixed to the bottom of the water tank. The breakwater 18 is fixed to the reef flat 15, and the topographic surveying device 19 is fixed to the water tank frame.

[0029] like Figure 1 and Figure 3 This is a schematic diagram illustrating the construction of the foreshore slope 15 and the aftshore slope 17 of the present invention. Figure 1 and Figure 3 In the frame, aluminum alloy profiles 1 are connected to each other by profile connecting corner pieces 2 to form a frame, and stainless steel plates 3 are fixed to the upper surface of the frame by T-bolts and nuts 4.

[0030] like Figure 2 This is a schematic diagram of the frame structure of the reef flat model 16 of the present invention. Figure 2 In the process, aluminum alloy profiles 1 are connected to each other through profile connecting corner pieces 2 to form a frame, acrylic plates 5 are connected to form a flushing groove with waterproof adhesive, the flushing groove is fixed to the frame with T-bolts and nuts 4, and calcium sand of different particle sizes and roughness is laid in the flushing groove.

[0031] like Figure 5 and Figure 6These are schematic diagrams and cross-sectional views of the breakwater model and the wave measurement device 18 of the present invention. The breakwater model is welded from stainless steel plates 3, with several nuts 9 pre-installed on the front surface. The breakwater model and the stainless steel outer shell 12 are welded together via stainless steel pipes 10. A water collection tank 13 and a weighing instrument 14 are housed inside the stainless steel outer shell 12. The water collection tank 13 is placed on top of the weighing instrument 14. One end of the guide channel 11 is connected to the top of the breakwater model, and the other end is connected to the water collection tank 13.

[0032] like Figure 4 This is a schematic diagram of the structure of the topographic surveying device 14 of the present invention. Figure 4 In the middle, the slide rail 6 is fixed on the water tank frame, the aluminum alloy profile 1 is connected to the slider 7 on the slide rail 6 by T-bolts and nuts 4, and the terrain scanner 8 is fixed below the aluminum alloy profile 1.

[0033] The testing process for the above-mentioned device is as follows:

[0034] First, an empty water tank was filtered in the experimental tank to ensure that waves with the specified wave height and period were generated by the wave generator. Then, a breakwater model of an island reef was placed in the experimental tank, and waves were generated using the wave generator. These waves propagated and deformed on the island reef terrain, causing extreme wave impacts and overtopping at the breakwater location, and localized scouring at the breakwater model location. Wave height changes and pressure distribution on the breakwater model were measured using wave height meters and pressure sensors. Overtopping was measured using an overtopping measurement device. The wave propagation deformation, impact, overtopping, and scouring processes were captured by a high-speed camera, and the images were processed and analyzed using MATLAB. The scourted terrain was scanned using a terrain scanner to obtain three-dimensional terrain data. The experiment was conducted under different experimental conditions to study the evolution of wave impacts, overtopping, and scouring at the island reef breakwater under different wave heights, wave periods, water depths, foreshore slopes, reef flat lengths, aft slopes, and breakwater locations.

[0035] Of course, the above are just specific application examples of the present invention. The present invention has other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. An experimental apparatus for studying the extreme wave impact, overtopping, and scouring evolution of breakwaters on islands and reefs, characterized in that: The system includes an experimental water tank, a high-speed camera located outside the water tank, and models of a reef front slope, reef flat, and reef back slope, a breakwater, and a wave overtopping device located at the bottom of the water tank, as well as a topographic measurement device located at the top of the water tank. The reef front slope, reef flat, and reef back slope models are sequentially connected to form the island and reef topography. The breakwater model and the wave overtopping device are located on top of the reef flat model. The topographic measurement device is used to scan the island and reef erosion topography during the experiment. The aforementioned reef front slope model and reef back slope model include aluminum alloy profiles and stainless steel plates. The aluminum alloy profiles are connected to each other through profile connecting corner pieces to form a frame, and the stainless steel plates are fixed to the surface of the frame by T-bolts and nuts. The reef flat model includes aluminum alloy profiles and acrylic panels. The aluminum alloy profiles are connected to each other to form a frame through profile connecting corner pieces. The acrylic panels are used to form a roofless cuboid scouring trough with waterproof adhesive. The scouring trough is fixed to the frame with T-bolts and nuts. Calcium sand is laid in the scouring trough. The breakwater model described is a sloping breakwater, welded from stainless steel plates, with nuts on the surface for connecting pressure sensors. The wave overpass measurement device includes a guide channel, a stainless steel pipe, a stainless steel shell, and a water collection tank. The breakwater model and the stainless steel shell are welded together by the stainless steel pipe. The water collection tank and a weighing instrument are installed inside the stainless steel shell. One end of the guide channel is connected to the top of the breakwater model, and the other end is connected to the water collection tank. The weighing instrument is located at the bottom of the water collection tank and is used to measure the wave overpass amount when waves pass over the breakwater model.

2. The experimental apparatus for studying the extreme wave impact, overtopping, and scouring evolution of island and reef breakwaters according to claim 1, characterized in that: The breakwater model is equipped with a pressure sensor on its surface to measure the pressure distribution on the breakwater model surface; the experimental water tank is equipped with a wave height meter along the wave path to measure the wave height change during wave propagation.

3. The experimental apparatus for studying the extreme wave impact, overtopping, and scouring evolution of island and reef breakwaters according to claim 1, characterized in that: The terrain surveying device includes a slide rail, an aluminum alloy profile, and a terrain scanner. The slide rail is fixed to the water tank frame by bolts and nuts. The aluminum alloy profile is connected to the slider on the slide rail by T-bolts and nuts. The terrain scanner is fixed below the aluminum alloy profile and can move along the slide rail.

4. An experimental method for studying the extreme wave impact, overtopping, and scouring evolution of breakwaters on islands and reefs, characterized in that, This method is implemented based on the apparatus described in any one of claims 1-3, and the steps are as follows: First, an empty water tank was filtered in the experimental tank to ensure that waves of the specified height and period were generated by the wave generator. Then, models of the foreshore slope, reef flat, aft slope, and breakwater were arranged in the experimental tank. Waves were generated using the wave generator to study wave propagation, evolution, slamming, overtopping, and scouring processes. Overtopping volume was measured on the breakwater model using an overtopping measurement device. Wave height changes and pressure distribution on the breakwater model surface were measured using a wave height meter and pressure sensor. High-speed cameras were used to capture wave slamming, overtopping, and scouring processes. MATLAB scripts were used to process and analyze the acquired images to obtain two-dimensional topographic time-history changes during the scouring process. A topographic scanner was used to scan the scourted terrain to obtain three-dimensional topographic data. By analyzing the experimental data, the extreme wave slamming, overtopping, and scouring evolution processes of the island and reef breakwater under different wave heights, wave periods, water depths, foreshore slope gradients, reef flat lengths, aft slope gradients, and breakwater locations were studied.

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