Bottom friction dissipation is a key factor for wave attenuation in nearshore environments presenting complex geomorphological structures, such as rocky or coral shores. The present paper reports on a series of laboratory experiments performed in a wave flume with controlled wave conditions and seabed structures. Using the frequency-integrated short-wave analysis and classical models for bottom friction and breaking dissipation, the wave friction factor and the hydraulic roughness parameter were estimated from the experimental data. The former varies from 0.17 to 98 while the latter varies from 0 to 0.291 m. The observations reveal the combined influence of several topographical metrics, including the standard deviation, the skewness, the directionality and the effective slope of the seabed elevation. A metric-based multi-varied model for the hydraulic roughness parameter is proposed and confronted with other field data recovered on coral and rocky shores.

中文翻译：

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粗糙度几何形状在摩擦波耗散中的作用

底部摩擦耗散是近岸环境中波浪衰减的关键因素，这些环境具有复杂的地貌结构，例如岩石或珊瑚海岸。本文报告了在受控波浪条件和海底结构的水槽中进行的一系列实验室实验。利用频率积分短波分析和底部摩擦和破碎耗散的经典模型，根据实验数据估算了波浪摩擦系数和水力粗糙度参数。前者的变化范围为0.17至98，而后者的变化范围为0至0.291 m。观测结果揭示了多种地形指标的综合影响，包括海底高程的标准差、偏斜度、方向性和有效斜率。提出了一种基于度量的水力粗糙度参数多变量模型，并与在珊瑚和岩石海岸上恢复的其他现场数据进行比较。