Accession Number:

ADA409070

Title:

Experimental Study of 3D Localized Boundary-Layer Receptivity to Free-Stream Vortices by Means of Two-Source Method

Descriptive Note:

Conference paper

Corporate Author:

RUSSIAN ACADEMY OF SCIENCES NOVOSIBIRSK INST OF THEORETICAL AND APPLIED MECHANICS

Report Date:

2002-07-01

Pagination or Media Count:

7.0

Abstract:

The investigation of mechanisms of excitation of the boundary-layer instability waves by various external perturbations represents an important aspect of the laminar-turbulent transition problem and has a crucial significance for both basic research of transition and practical applications. A review of recent studies in this field related to 3D receptivity problems for 2D and 3D boundary layers can be found. Most of previous experimental investigations were devoted to the receptivity to surface perturbations roughness and vibrations and to acoustic waves. Meanwhile, the excitation of instability waves by free-stream turbulence can also play a very important role and influence the transition process. The present paper is devoted to an experimental investigation of the 3D receptivity of Blasius boundary layer to non-stationary vortical free-stream disturbances due to their scattering on localized in streamwise and spanwise directions surface vibrations. There is only one available quantitative experimental study of a similar receptivity problem performed for unsteady free-stream vortices. A scattering of a weak vortex street with 2D spanwise vorticity on a localized two-dimensional surface roughness has been studied in this work in the Blasius flow. The results of this experiment were found to be in a good agreement with the 2D receptivity theory. Three-dimensional receptivity to non-stationary free-stream vortices has not been studied in previous experiments at all. The scattering of free-stream vortices on surface vibrations was not studied even for purely two-dimensional case.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE