Author(s): Ram Balachandar; Deighen Blakely
Keywords: Open channel flow; surface roughness; mean velocity; turbulence; velocity skewness; flatness factor; roughness Reynolds number
Abstract: The effect of surface roughness on turbulent boundary layers on a flat plate located in an open channel is investigated at moderately high Froude numbers (0.25 < Fr < 1.1) and low momentum thickness Reynolds numbers (550 < Re θ < 3400). Two of the rough walls are composed of sand grains while the third is made of a wire mesh. The present results indicate that in shallow open channel flows, the roughness effects permeate through most of the boundary layer. The fullness of the mean velocity profiles, the wake parameter and the turbulence intensity profiles were found to depend on the roughness function and Reynolds number.