Turbulence and Shear Flow Phenomena -1 First International Symposium

ISBN Print: 1-56700-135-1

DIRECT NUMERICAL SIMULATIONS OF TURBULENT FLOW OVER MOVING SINUSOIDAL BOUNDARIES

Abstract

Turbulent flow over idealized water waves is investigated using direct numerical simulations at a bulk Reynolds number Re = 8000 over non-evolving water waves with varying waveslope αk and wave age c/u* . The results show that waves significantly influence the mean flow, vertical momentum fluxes, velocity variances, pressure, and form stress (drag). Compared to a stationary wave, slow (fast) moving waves increase (decrease) the form stress. A region of closed streamlines (or cat's-eye pattern) centered about the critical layer height was observed at low to moderate values of c/u* and was found to be dynamically important in determining the mean flow, turbulent fluxes, and surface form stress.