Accession Number : ADA311347

Title :   Theoretical and Numerical Study of Asymmetric Unsteady Lex and Slender-Wing Vortices Including Breakdown.

Descriptive Note : Final rept. 1 Jan 92-30 Sep 95,

Corporate Author : NOTRE DAME UNIV IN DEPT OF AEROSPACE AND MECHANICAL ENGINEERING

Personal Author(s) : Cheung, K. ; Jumper, E. J. ; Nelson, R. C.

PDF Url : ADA311347

Report Date : NOV 1995

Pagination or Media Count : 12

Abstract : The following final report documents the accomplishments made under AFOSR Grant F49620-92-J-9105 for the period starting January 1, 1992 and ending September 30, 1995. During this time, progress was made in better understanding the spiral vortex breakdown phenomenon. A theoretical model of vortex breakdown was developed illustrating the self-induced cause-and-effect nature of the breakdown spiral in sustaining its geometry in an adverse pressure field. From this study a geometric compatibility condition was discovered in the form of a non-dimensional circulation strength. Experiments were conducted to experimentally confirm this geometric compatibility condition. An isolated vortex was subjected to two breakdown-inducing flowfields; the first consisted of a flow obstruction, and the second consisted of a pair of counter-rotating cylinders. The geometric compatibility condition was found to exist for the resulting spiral vortex breakdown from both of the experiments. Three papers were written and presented on this study at several AIAA Applied Aerodynamics conferences, and a journal paper is currently under review. Also, an abstract was submitted in October, 1995 for an AIAA Applied Aerodynamics conference in 1996.

Descriptors :   *VORTICES, *WING BODY CONFIGURATIONS, PRESSURE GRADIENTS, SLENDER BODIES, COMPUTATIONAL FLUID DYNAMICS, FLOW VISUALIZATION, FLOW FIELDS, WIND TUNNEL TESTS, UNSTEADY FLOW, FREE STREAM, DELTA WINGS, PRESSURE DISTRIBUTION, AXIAL FLOW.

Subject Categories : Fluid Mechanics
      Aerodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE