Near-Wall Response of Unsteady Turbulent Flows. Part I. Fluid Dynamics

The near-wall response of periodically-forced turbulent flows is considered and we deal with the fluid dynamical and computational aspects of the problem in this paper.The corresponding.modulated turbulent Stokes layer problemis solved with extensions of the rapid distortion theory, precisely in the frequency range where quasi-steady assumptions would fail.The computed unsteady velocity oscillat ions and modulated turbulent stresses compare favorably with observations in the "non quasi steady" frequency ranges.This forms the basis for the acoustical acpects of the problem to be reported subsequently.