THE EFFECT OF BED PERMEABILITY ON OSCILLATORY BOUNDARY LAYER FLOW

Kathryn Sparrow, Dubravka Pokrajac, Dominic A van der A

Abstract


This experimental study consists of a series of full-scale experiments involving oscillatory boundary layer flow over an impermeable bed and a permeable bed. Velocity measurements have been obtained through particle image velocimetry, and the effect of bed permeability on the velocity profile, phase lead, boundary layer thickness, bed shear stress (as estimated by fitting the log law), and finally the resulting friction factor is presented. For our rough turbulent flows over a permeable bed it has been found that the friction factor is increased by up to 36% and that the friction factor also demonstrates a dependence on Reynolds number.

Keywords


oscillatory flow; boundary layer; permeable bed.

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