Estimate of Drag Coefficient for a Finite Patch of Rigid Cylinders

Abstract

This note presents laboratory measurements of the drag coefficient for a finite patch of vegetation that was simulated with a limited number of rigid cylindrical rods. The experiment was designed based on an analogy between the drag imposed by a vegetation patch in an open-channel flow and that experienced by the patch settling in a water tank. The results show that the average drag coefficient calculated from the measured settling velocity can be expressed as a function of the patch porosity. The experimental data are also consistent with previous predictions by large eddy simulations.