Accession Number : ADA271548

Title :   On the Receptivity Problem for 0(1) Wavelength Gortler Vortices.

Descriptive Note : Contractor rept.,

Corporate Author : INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON VA

Personal Author(s) : Bassom, Andrew P. ; Hall, Philip

Report Date : AUG 1993

Pagination or Media Count : 25

Abstract : In this paper we make an investigation of the receptivity of boundary layer flows to Gortler vortex modes. A study by Denier, Hall, and Seddougui (1991) of the generation of vortices by wall roughness elements concluded that such elements are extremely poor as mechanisms to stimulate short wavelength modes. That work also examined the equivalent problem pertaining to O(1) wavelength modes but that analysis was in error. We re-examine this problem here and demonstrate how the form of the wall roughness is crucial in determining the vortex stability characteristics downstream of the roughness. In particular we investigate the cases of both isolated and distributed forcing functions and show that in general a distributed function is much more important in generating vortices than are either isolated roughness or free-stream disturbances. Receptivity, Vortex.

Descriptors :   *BOUNDARY LAYER FLOW, *TRAILING VORTICES, ERRORS, SHORT WAVELENGTHS, STABILITY, WALLS, SURFACE ROUGHNESS.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE