Flow conditions, bed form dimensions and shear stress experiments

Large asymmetric bed forms commonly develop in rivers. The turbulence associated with flow separation that develops over their steep lee side is responsible for the form shear stress which can represent a substantial part of total shear stress in rivers. This paper uses the Delft3D modeling system to investigate the effects of bed form geometry and forcing conditions on flow separation length and associated turbulence, and bed form shear stress over angle-of-repose (30 lee side angle) bed forms. The model was validated with lab measurements that showed sufficient agreement to be used for a systematic analysis. […]

在河流中，大型非对称床沙形态普遍形成。与床沙形态陡峭背水侧形成的分离流相关的湍流，是导致床沙形态剪切应力的主要原因，这可以构成河流总剪切应力中相当一部分。本文采用Delft3D模拟系统，探究床沙形态几何形状及驱动力条件对分离流长度及其相关湍流、以及床沙形态剪切应力在休止角（30度背水侧角度）床沙形态上的影响。该模型通过与实验室测量结果进行验证，显示出的足够一致性，可用于系统分析。