Comparison of Theory and Direct Numerical Simulations of Drag Reduction by Rodlike Polymers in Turbulent Channel Flows

摘要

Numerical simulations of turbulent channel flows, with or without additives,are limited in the extent of the Reynolds number \Re and Deborah number \De.The comparison of such simulations to theories of drag reduction, which areusually derived for asymptotically high \Re and \De, calls for some care. Inthis paper we present a study of drag reduction by rodlike polymers in aturbulent channel flow using direct numerical simulation and illustrate howthese numerical results should be related to the recently developed theory.