OSCILLATORY BOUNDARY LAYER FLOW OVER RIPPLED BEDS

Proceedings of the International Conference on Coastal Engineering

Akira Watanabe²  Shinji Sato¹  Nobuo Mimura³ 

[1] Dept. of Civil Eng., Univ. of Tokyo;Dept. of Civil Eng., Univ. of Tokyo, Bunkyo-ku, Tokyo;Dept. of Civil Eng., Ibaraki Univ., Hitachi

关键词: rippled bed;    boundary layer flow;    oscillatory flow;   

DOI  :  10.9753/icce.v19.%p

学科分类：建筑学

来源: Coastal Engineering Research Council

【 摘 要 】

Characteristics of the oscillatory boundary layer flow above rippled beds were investigated through experiments and numerical calculations. Experiments were conducted in an oscillatory flow tunnel. Velocities above symmetric and asymmetric ripples were measured with split-hot-film sensors under conditions of both sinusoidal and asymmetric oscillations. The stress field in the boundary layer was evaluated based on the distributions of the measured velocity and Reynolds stress. Relations between vortex formation and turbulence were examined, and effects of the asymmetry of oscillatory main flow and of ripple form on the velocity field were discussed. Numerical calculations were carried out by integrating the Navier-Stokes equations with an implicit finite difference scheme. Formation of a lee vortex above ripples was simulated in the calculations. The bottom shear stress and the energy dissipation rate were estimated based on the results of the experiments and calculations.

【 授权许可】

Unknown