Drag Coefficient for Porous Screen in a Non-Oscillating Perpendicular to Plane-in Flow

Abstract

The flow-through porous bodies/structure is one of the more advanced research in the area of energy dissipation in coastal and civil engineering fields. The experiments on the determination of drag coefficient of screens with varying porosities and for the range of flow velocities lead to explore damping ratio in a typical fluid-structure interaction problem. An experimental study has been carried out to assess the drag coefficient of the porous screens as suggested by Keulegan, G. H (1968) [3]. Six different screens with porosities of 4.4%, 6.8%, 9.2% 15%, 20% and 25% are considered. In the experiments, water with a known head from one tank is allowed to flow through a pipe equipped with porous screens into the other tank. Based on the experimental observation, the correlation between Reynolds number and drag coefficient is obtained for all porous screens. The effect of damping nature (damping ratio) of the screen for a particular range of Reynolds number has been explored. As the Reynolds number increases, the drag coefficient decreases with increasing the porosity of the screen. Further, it is understood that the value of the damping ratio decreases with an increasing relative head (H/L).