This animation shows vortex generation in three-dimensions due to an isolated spherical roughness element in the presence of an oscillatory boundary layer at Re_D=1000, bD=14, e/D=0.375. The external flow is imposed by a sinusoidally varying body force. The Reynolds number, based upon peak far-field velocity, radius, and kinematic viscosity, is Re=1000. The period of oscillation is 16.0285 convective time units (D/U), corresponding to a Stokes layer thicknes of D/14.
Last update: October 4, 1999 (pff)