Accession Number : ADA303627

Title :   Shear Layer Breakdown in Compressible Flow.

Descriptive Note : Final rept. 1 Nov 91-1 Nov 95,

Corporate Author : LEHIGH UNIV BETHLEHEM PA DEPT OF MECHANICAL ENGINEERING AND MECHANICS

Personal Author(s) : Walker, J. D.

PDF Url : ADA303627

Report Date : 15 NOV 1995

Pagination or Media Count : 13

Abstract : This is a final report describing research carried out on the physical processes of breakdown of unsteady boundary layer flows at high Reynolds numbers. The research is relevant to processes occurring in dynamic stall and transition to turbulence and concerns the complex physical processes that can occur when a boundary layer separates from a rigid wall. The results indicate that very complicated responses develop in the surface pressure, in some cases leading to instability. It has been shown how the boundary layer can break down locally and lead to a process of explosive windup into a new vortex structure. The theory appears to be consistent with and explains the breakdowns observed in experiments, as well as direct simulations of turbulent and transitional flows.

Descriptors :   *STALLING, *BOUNDARY LAYER TRANSITION, TURBULENCE, VORTICES, COMPRESSIBLE FLOW, FLOW FIELDS, PRESSURE, UNSTEADY FLOW, INSTABILITY, REYNOLDS NUMBER.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE