The evolution of ripple geometries and their equilibrium states due to different wave forcing parameters are investigated by a Reynolds-averaged two-phase model, SedFoam, in a two-dimensional domain. Modeled ripple geometries, for a given uniform grain diameter, show a good agreement with ripple predictors that include the wave period effect explicitly, in addition to the wave orbital excursion length (or wave orbital velocity amplitude). Furthermore, using a series of numerical experiments, the ripple's response to a step-change in the wave forcing is studied. The model is capable of simulating “splitting,” “sliding,” “merging,” and “protruding” as the ripples evolve to a new equilibrium state. The model can also simulate the transition to sheet flow in energetic wave conditions and ripple reformation from a nearly flat bed condition. Simulation results reveal that the equilibrium state is such that the “primary” vortices reach half of the ripple length. Furthermore, an analysis of the suspended load and near-bed load ratio in the equilibrium state indicates that in the orbital ripple regime, the near-bed load is dominant while the suspended load is conducive to the ripple decaying regime (suborbital ripples) and sheet flow condition.

中文翻译：

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欧拉两相模型揭示了波浪周期在波纹演化和平衡几何中的重要性

由雷诺平均两相模型 SedFoam 在二维域中研究了由于不同的波浪强迫参数引起的波纹几何形状及其平衡状态的演变。对于给定的均匀晶粒直径，建模的波纹几何形状与波纹预测器非常吻合，除了波轨道偏移长度（或波轨道速度幅度）外，还明确包括波周期效应。此外，使用一系列数值实验，研究了波纹对波浪强迫阶跃变化的响应。随着涟漪演化到新的平衡状态，该模型能够模拟“分裂”、“滑动”、“合并”和“突出”。该模型还可以模拟在高能波条件下向片状流的转变以及从近乎平坦的床条件下的波纹重构。仿真结果表明，平衡状态是“主要”涡流达到波纹长度的一半。此外，对平衡状态下悬载与近床载比的分析表明，在轨道波纹状态下，近床载占主导地位，而悬载有利于波纹衰减状态（亚轨道波纹）和片状。流动状况。