Large-eddy substitution via vortex cancellation for wall turbulence controlA system of co-rotating longitudinal vortices was used to introduce streamline (as opposed to wall) curvature into a turbulent wall flow. Two methods of vortex cancellation, unwinding and self-annihilation, were tested as a means of removing the vortices once they had processed most of the incoming turbulent boundary layer. Vortex unwinding, which uses vorticity of the opposite sign, was shown to be a viable method for cancelling the co-rotating vortices. Vortex self-annihilation, caused by interference effects resulting from a close initial spanwise vortex spacing, eliminated the vortices within 60 delta downstream. In each case, reductions in boundary layer entrainment were found once the vortices were cancelled.
Document ID
19850043791
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Mcginley, C. B. (NASA Langley Research Center Hampton, VA, United States)
Beeler, G. B. (NASA Langley Research Center High-Speed Aerodynamics Div., Hampton, VA, United States)