DNS for Turbulent Drag Reduction at ${Re_\tau }=1600$

Abstract

This study considers the skin friction drag reduction of turbulent flow at high Reynolds numbers. A recent DNS study of flow control found that drag reduction became less effective as the Reynolds number increased from ${Re_\tau }=200$ to 1600 (Hurst et al. 2014). To investigate this Reynolds number effect, the drag reduction of the stationary waves is decomposed into laminar and turbulent components, and the turbulent contribution is further decomposed into inner and outer regions. The current analysis based on the Reynolds number up to ${Re_\tau }=1600$ appears to suggest that the Reynolds number effect on the drag reduction could be relatively modest than suggested in the previous studies, and this could mean that a significant drag reduction could be achieved at a flight condition.