A Large Eddy Simulation model is developed to simulate the hydrodynamics and scour process around a circular cylinder. The Navier-Stokes solver is based on the projection method and a second-order unstructured finite-volume method. A sigma-coordinate system is used to obtain an accurate representation of the evolution of the sediment-water interface. Bed erosion is simulated by solving the sediment continuity equation using a mass-conservating sand-slide algorithm and a bedload transport rate, which is based on a description of physical processes (Engelund & Fredsøe, 1976). Simulations of flow around a vertical cylinder for free-slip bed, rigid bed, and live-bed cases are done. The mean velocity profile and shear stress validate the accuracy of this model. Horseshoe vortex and lee-wake vortex shedding structure are simulated, and the results are thoroughly discussed in depth. The formation and the temporal development of the scour hole and other topographic bed features are successfully reproduced. The current paper reports the first known investigation of both scour evolution and coherent structure using large-eddy simulation.

开发了大型涡流仿真模型，以模拟圆柱体周围的水动力和冲刷过程。Navier-Stokes求解器基于投影方法和二阶非结构化有限体积方法。使用sigma坐标系来获得沉积物-水界面演变的准确表示。床身侵蚀是通过使用质量守恒的砂滑算法和床身输运速率来求解沉积物连续性方程来模拟的，床身输运速率基于对物理过程的描述（Engelund＆Fredsøe，1976）。对自由滑床，刚性床和活动床箱的垂直圆柱体周围的流动进行了仿真。平均速度曲线和切应力验证了该模型的准确性。模拟了马蹄涡和背风涡流的脱落结构，并对结果进行深入讨论。成功地再现了冲刷孔和其他地形床特征的形成和时间发展。本论文报道了使用大涡模拟对冲刷演化和相干结构的首次已知研究。