Pressure Drop Through Anisotropic Porous Mediumlike Cylinder Bundles in Turbulent Flow Regime

Abstract

Pressure drop through anisotropic porous mediumlike cylinder bundles is experimentally examined in turbulent flow regime. Three porosities, ε=0.66, 0.82, and 0.90, are considered. The flow blockage by the cylinder bundles is varied, with the yaw angle (α) used as an anisotropic measure. When the yaw angle is fixed while the porosity is varied, the pressure drop behaves as predicted by the force balance model, consistent with the classic observation: The pressure drop is proportional to the square of the flow velocity with the empirical proportionality as a function of (1−ε1∕2)∕ε2 obtained from the force balance model compared to that of (1−ε)∕ε3 from the hydraulic radius theory. On the other hand, for a given porosity, topological anisotropy of the cylinder bundles causes the sinusoidal response of the pressure drop to the variation of yaw angle. At α=0deg with a 60deg period, the lowest pressure drop occurs from the most open configuration of the cylinder bundle whereas the largest flow blockage at α=30deg causes the highest pressure drop. This variation appears to result from an increase in the drag coefficient of each cylinder element in a harmonic manner.