Transient response of Reynolds stress transport to spanwise wall oscillation in a turbulent channel flow

Turbulent channel flow at low Reynolds number subjected to spanwise wall oscillation is studied by direct numerical simulation. The Reynolds stress budgets under the influence of the oscillating wall are analyzed in the first two oscillation periods. It is found that the spanwise velocity fluctuations are enhanced at the very beginning of the wall oscillation, and the subsequent global turbulence suppression is caused by the sustained attenuation of the pressure-strain terms. The hindrance of intercomponent transfer of turbulent kinetic energy by the oscillating wall is a mechanism of the skin-friction reduction. (C) 2005 American Institute of Physics.