ABSTRACT A Lagrangian particle-based two-phase flow model is developed to simulate the scouring process induced by standing wave in front of the trunk section of a vertical breakwater. Given the two-dimensional nature of the scouring problem at the trunk of vertical wall, the fluid phase is simulated with two-dimensional Navier–Stokes equations based on weakly compressible smoothed particle hydrodynamics (WCSPH) formulation in conjunction with sub-particle scale (SPS) turbulence closure model. The sediment phase is simulated using the Discrete Element Method (DEM). The effects of interparticle and particle-wall collisions are computed by activating a spring-dashpot system. The WCSPH fluid-phase and DEM sediment-phase are coupled through a weakly one-way coupling procedure using wave orbital velocity. The numerical model is successfully validated against experimental data. The maximum scour depth predicted by WCSPH-DEM model is closely approximate the experimental data. This study, for the first time, demonstrated an extra recirculating sediment transport mechanism in front of the vertical breakwater, similar to steady streaming recirculating cells in the fluid phase, which has a direct impact on the formation of scour hole and maximum scour depth at the breakwater trunk. The scenario modeling conducted in this study show that by increasing the steady streaming velocity, the deposition rate and the depth of scour hole were increased.

中文翻译：

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立式防波堤前冲刷的拉格朗日两相流模型

摘要 开发了一个基于拉格朗日粒子的两相流模型来模拟垂直防波堤主干段前驻波引起的冲刷过程。鉴于垂直壁主干处冲刷问题的二维性质，基于弱可压缩平滑粒子流体动力学 (WCSPH) 公式结合亚粒子尺度 (SPS) 使用二维纳维-斯托克斯方程模拟流体相) 湍流闭合模型。沉积相使用离散元法 (DEM) 进行模拟。通过激活弹簧缓冲器系统来计算粒子间和粒子壁碰撞的影响。WCSPH 流体相和 DEM 沉积相通过使用波轨道速度的弱单向耦合程序进行耦合。该数值模型已成功地根据实验数据进行验证。WCSPH-DEM 模型预测的最大冲刷深度与实验数据非常接近。本研究首次证明了垂直防波堤前的额外循环泥沙输运机制，类似于流体相中的稳流再循环细胞，直接影响了冲刷孔的形成和最大冲刷深度。防波堤树干。本研究中进行的情景建模表明，通过增加稳定流速度，沉积速率和冲刷孔深度增加。在垂直防波堤前展示了一种额外的再循环泥沙输运机制，类似于流体相中的稳流再循环细胞，这对防波堤主干处冲刷孔的形成和最大冲刷深度有直接影响。本研究中进行的情景建模表明，通过增加稳定流速度，沉积速率和冲刷孔深度增加。在垂直防波堤前展示了一种额外的再循环泥沙输运机制，类似于流体相中的稳流再循环细胞，这对防波堤主干处冲刷孔的形成和最大冲刷深度有直接影响。本研究中进行的情景建模表明，通过增加稳定流速度，沉积速率和冲刷孔深度增加。