Large-Eddy Simulation (LES) of turbulent channel flow over rough beds: Rough Bed generation

The turbulent flow over a rough bed is one of the main concerns in modern Computational Fluid Dynamics. In flows of hydraulic engineering the walls of interest e.g. the river bank or the bed are often rough. To account for the roughness the Large-Eddy Simulation is used in this book. One of the challenges in LES is the accurate inclusion of wall roughness. Similarly as the knowledge of the velocity profile of a smooth wall, the velocity profile over a rough wall is needed. The specification itself is not an easy task. Especially the law of the wall for a rough bed is still subject of ongoing research. There are several techniques available to deal with this problem. In this book a porous medium and artificially generated rough elements are used to simulate wall roughness.