A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand

Thesis (M.Eng.) - Asian Institute of Technology, 1977

The research reported. herein was conducted to study the characteristics of the velocity distribution and the vortex formation in the oscillatory boundary layer above the wavy bottom. This study includes numerical calculation based on Navier-Stokes equation and the finite difference method. Numerical calculation technique proposed by Carl Pearson were developed to get the stream function, vorticity, and velocity distributions within the oscillatory boundary layer above the wavy bottom. Calculation were carried out for different conditions of flow and bottom roughness and results were compared with the experimental results for the corresponding case. It was concluded in this report that the horizontal and vertical velocity components are related to the magnitudes of the ·Reynolds, number and bottom roughness. The formation of the vortex around the ripple are related strongly to Reynolds number and slightly to bottom roughness. For high Reynolds number case, the presence of large vortices distorts not only the vertical velocity but also the horizontal velocity within the oscillatory boundary layer.