The propagation and evolution characteristics of tsunami-like waves over complex reefs topography and their impact on sea walls
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摘要: 真实海洋环境中的岛礁通常具有复合式地貌，礁坪往往呈现出非平整的特征。以往大量的研究工作主要关注简化的台阶式岛礁模型，并未对复合式岸礁非平整礁坪对波浪传播演变特性的影响开展深入的研究工作。为了弥补前人研究的不足，本文开展了物理模型试验，系统研究了类海啸波在复合式岸礁上的传播演变特性，以往的研究并没有考虑礁坪地形的非平整性对孤立波带来的影响，因此本文分析了入射波高、礁坪水深的影响。为了研究不同入射波条件下非平整礁坪几何特征对类海啸波传播演变以及海墙载荷特性的影响，本文进一步开展了一系列的高分辨率数值计算。先通过物理试验来验证数值模拟方法的准确性，再用数值计算研究了孤立波的入射波高和礁坪淹没水深2种波浪要素以及第二礁坪高度、礁坪台阶位置和礁前斜坡坡度3种复杂岛礁地形因素影响下孤立波的沿程最大波高、反射系数、最大爬高、海墙的最大冲击压强分布、海墙的最大总力与总力矩的变化规律。研究结果表明：孤立波的反射系数随入射波高的增大而减小，随礁坪水深的增大而增大，最大爬高随入射波高的增大而增大，随礁前斜坡的cot α增大而减小。海墙的最大总力与最大总力矩随入射波高和礁坪水深的增大而增大，随第二礁坪的高度增大而降低。海墙上最大冲击压强出现的位置会随入射波高的增大、礁坪水深的增大、礁坪台阶距离海墙距离的减小而上升。研究结果可为进一步保护沿海设施免受极端海洋环境的影响提供一定的参考。Abstract: In real ocean environments, natural reefs typically exhibit complex topography, with reef platforms presenting non-uniform characteristics. Previous extensive research has mainly focused on simplified stepped reef models and has not conducted in-depth studies on the impact of non-uniform reef platforms on the propagation and evolution characteristics of waves. To address the shortcomings of previous research, this paper conducted physical model experiments to systematically study the propagation and evolution characteristics of tsunami-like waves over complex reef platforms. Previous studies did not consider the impact of the non-uniformity of reef platform topography on solitary waves, therefore, this paper also analyzed the effects of incident wave height and reef platform water depth. To investigate the impact of non-uniform reef platform geometric characteristics on the propagation and evolution of tsunami-like waves and the load characteristics of sea walls under different incident wave conditions, this paper further carried out a series of high-resolution numerical calculations. First, physical experiments were used to verify the accuracy of the numerical simulation method, and then numerical calculations were used to study the effects of two wave parameters, incident wave height and reef platform submergence depth, and three complex reef topography factors—the height of the second reef platform, the position of the reef platform steps, and the slope of the reef front slope—on the maximum wave height along the path, reflection coefficient, maximum run-up height, distribution of the maximum impact pressure on the sea wall, and the variation of the maximum total force and total moment on the sea wall. The research results indicate that the reflection coefficient of solitary waves decreases with increasing incident wave height and increases with increasing reef platform water depth. The maximum run-up height increases with increasing incident wave height and decreases with increasing cot α of the reef front slope. The maximum total force and maximum total moment on the sea wall increase with increasing incident wave height and reef platform water depth, and decrease with increasing height of the second reef platform. The position of the maximum impact pressure on the sea wall rises with increasing incident wave height, increasing reef platform water depth, and decreasing distance between the reef platform steps and the sea wall. The research results can provide a reference for further protecting coastal facilities from the impact of extreme marine environments.
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Key words:
- tsunami-like waves /
- non-uniform reef /
- sea wall /
- maximum run-up height /
- impact pressure
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图 2 试验所求不同波浪要素下孤立波的反射系数与最大爬高
Fig. 2 The reflection coefficients and maximum run-up of solitary waves under different wave elements as required by the experiment
图 3 流速和爬高的时间序列对比（左为流速，右为爬高）
Fig. 3 Time series comparison of flow velocity and run-up (left for flow velocity, right for run-up)
图 6 不同入射波高下孤立波的沿程最大波高分布
Fig. 6 Distribution of maximum wave height along the path of solitary waves under different incident wave heights
图 7 不同入射波高下海墙所受最大压强的沿墙分布（左侧：含静水压强，右侧：动水压强）
Fig. 7 Distribution of maximum pressure along the seawall under different incident wave heights (left: including static water pressure, right: dynamic water pressure)
图 8 不同入射波高下海墙所受最大总力与最大总力矩
Fig. 8 The maximum total force and torque received by the sea wall under different incident wave heights
图 9 不同礁坪水深下孤立波的沿程最大波高分布
Fig. 9 Distribution of maximum wave height along the path of solitary waves under different reef flat water depths
图 10 不同礁坪水深下海墙所受最大压强的沿墙分布（左侧：含静水压强，右侧：动水压强）
Fig. 10 Distribution of maximum pressure along the seawall under different reef flat water depths(left: including static water pressure, right: dynamic water pressure)
图 11 不同礁坪水深下海墙所受最大总力与最大总力矩
Fig. 11 Maximum total force and maximum total moment on the seawall under different reef flat water depths
图 12 不同第二礁坪高度下孤立波的沿程最大波高分布
Fig. 12 Distribution of maximum wave height along the path of solitary waves under different second reef flat heights
图 13 不同第二礁坪高度条件下孤立波的反射系数、最大爬高、海墙所受最大总力与最大总力矩
Fig. 13 Reflection coefficients, maximum run-up, maximum total force, and maximum total moment on the seawall for solitary waves under different second reef flat height conditions
图 14 不同第二礁坪高度下海墙所受最大压强的沿墙分布（左侧：含静水压强，右侧：动水压强）
Fig. 14 Distribution of maximum pressure along the seawall under different second reef flat heights(left: including static water pressure, right: dynamic water pressure)
图 15 不同礁坪台阶位置下孤立波的沿程最大波高分布
Fig. 15 Distribution of maximum wave height along the path of solitary waves under different reef flat step positions
图 16 不同礁坪台阶位置条件下孤立波的反射系数、最大爬高、海墙所受最大总力与最大总力矩
Fig. 16 Reflection coefficients, maximum run-up, maximum total force, and maximum maximum total moment on the seawall for solitary waves under different reef flat step position conditions
图 17 不同礁坪台阶位置下海墙所受最大压强的沿墙分布（左侧：含静水压强，右侧：动水压强）
Fig. 17 Distribution of maximum pressure along the seawall under different reef flat step positions (left: including static water pressure, right: dynamic water pressure)
图 18 不同礁前斜坡坡度下孤立波的沿程最大波高分布
Fig. 18 Distribution of maximum wave height along the path of solitary waves under different front reef slope gradients
图 19 不同礁前斜坡坡度条件下孤立波的反射系数、最大爬高、海墙所受最大总力与最大总力矩
Fig. 19 Reflection coefficients, maximum run-up, maximum total force, and maximum total moment on the seawall for solitary waves under different front reef slope gradient conditions
图 20 不同礁前斜坡坡度下海墙所受最大压强的沿墙分布（左侧：含静水压强，右侧：动水压强）
Fig. 20 Distribution of maximum pressure along the seawall under different front reef slope gradients (left: including static water pressure, right: dynamic water pressure)
表 1 浪高仪位置
Tab. 1 Position of the wave height gauge
浪高仪编号 WG1 WG2 WG3 WG4 WG5 WG6 WG7 位置/m 12.8 13.121 13.679 19.372 23.85 24.642 25.535 浪高仪编号 WG8 WG9 WG10 WG11 WG12 WG13 WG14 位置/m 26.468 26.963 27.434 27.612 27.883 28.747 30.224 
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表 2 孤立波试验工况
Tab. 2 Solitary wave test conditions
H0 / m hr / m Hp / m Lp / m cot α 0.02，0.04，0.06，0.08，0.1 0，0.025，0.05，0.075 0.125 0.974 8.271
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表 3 孤立波的数值模拟验证工况
Tab. 3 Numerical simulation verification conditions for solitary waves
H0 / m h / m Hp / m Lp / m cot α 0.06 0.655 0.125 0.974 8.271
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表 4 不同入射波高下孤立波的数值模拟工况
Tab. 4 Numerical simulation working conditions for solitary waves under different incident wave heights
H0 / m h / m Hp / m Lp / m cot α 0.02，0.04，0.06，0.08，0.1 0.655 0.125 0.974 8.271
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表 5 不同礁坪水深下孤立波的数值模拟工况
Tab. 5 Numerical simulation working conditions for solitary waves on reef flats at different water depths
$h_r^{*} $ H0 / m Hp / m Lp / m cot α 0， 0.0397 ，0.0763 ，0.1100.06 0.125 0.974 8.271
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表 6 不同第二礁坪高度下孤立波的数值模拟工况
Tab. 6 Numerical simulation working conditions for solitary waves at different heights of the second reef
Hp / m H0 / m h / m Lp / m cot α 0.075，0.1，0.125，0.15，0.175 0.06 0.655 1 8
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表 7 不同礁坪台阶位置下孤立波的数值模拟工况
Tab. 7 Numerical simulation working conditions for solitary waves at different reef platform step positions
Lp / m H0 / m h / m Hp / m cot α 0，0.5，1，1.5，2 0.06 0.655 0.125 8
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表 8 不同礁前斜坡角度下孤立波的数值模拟工况
Tab. 8 Numerical simulation working conditions for solitary waves under different reef-front slope angles
cot α H0 / m h / m Hp / m Lp / m 4，6，8，10，12 0.06 0.655 0.125 1
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