On the pressure-strain correlation in fibrous drag-reduced turbulent channel flow

The pressure-strain correlation is studied in detail using the direct numerical simulation data obtained by a direct Monte-Carlo simulation of turbulent drag reduction in a channel flow caused by rigid fiber additives. This is used to analyze the energy redistribution process and to explain the pronounced anisotropy of the drag-reduced flow as compared to its Newtonian counterpart. Moreover, the change in pressure fluctuations and strain-rate fluctuations are studied to explain the modifications in the pressure-strain term. It is found that the reduction in strain-rate fluctuations is mainly responsible for the change in the pressure-strain term and the effect of pressure fluctuations is modest. (C) 2016 AIP Publishing LLC.