Accession Number : ADA309944

Title :   Thrust-Induced Effects on a Pitching-Up Delta Wing Flow Field.

Descriptive Note : Annual rept. 15 Oct 93-14 Oct 94,

Corporate Author : FLORIDA STATE UNIV TALLAHASSEE DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Lourenco, L. ; Shih, C. ; Van Dommelen, L. ; Krothapalli, A.

PDF Url : ADA309944

Report Date : 01 DEC 1994

Pagination or Media Count : 64

Abstract : The Thrust-induced effects on a pitching-up delta wing flow field are studied experimentally in a water towing tank facility. Previous report has shown that the jet has a significant effect in delaying the vortex breakdown over the delta wing. Strong asymmetric bursting of the leading edge vorticies can be induced by arranging the vectored jet' in an asymmetric configuration. Extensive PIV measurements have been made to confirm these results. It is shown that the jet induces large accelerated flow along the vortex core which leads to more effective transportation of vorticity downstream. As a result, the primary vorticies are stabilized and strengthened. Also, a quasi-periodic variation of the instantaneous vortical structure on the cross flow plane is observed. Concurrently, a numerical simulation technique based on the existing discrete vortex method is developed. A new grid-free 'Vorticity Redistribution' technique is used to handle vorticity diffusion process. A test case involves unsteady separation of flow over an impulsively started cylinder is studied using this new technique.

Descriptors :   *FLOW FIELDS, *DELTA WINGS, *THRUST AUGMENTATION, TEST AND EVALUATION, MATHEMATICAL MODELS, TRANSPORTATION, ACCELERATION, NUMERICAL ANALYSIS, VORTICES, DIFFUSION, NUMERICAL METHODS AND PROCEDURES, THRUST, CROSS FLOW, WATER TANKS, MODEL BASINS.

Subject Categories : Aerodynamics
      Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE