Open AccessOSCILLATORY BOUNDARY LAYER FLOW OVER RIPPLED BEDS
Author(s) -
Shigeo Sato,
Naoya Mimura,
Akira Watanabe
Publication year - 1984
Publication title -
proceedings of conference on coastal engineering/proceedings of ... conference on coastal engineering
Language(s) - English
Resource type - Journals
eISSN - 2156-1028
pISSN - 0589-087X
DOI - 10.9753/icce.v19.154
Subject(s) - boundary layer , mechanics , vortex , turbulence , shear stress , reynolds stress , flow (mathematics) , water tunnel , asymmetry , ripple , dissipation , boundary layer thickness , stress (linguistics) , physics , flow separation , classical mechanics , thermodynamics , power (physics) , linguistics , philosophy , quantum mechanics
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.