TWO-EQUATION TURBULENCE MODELING OF HYPERSONIC TRANSITIONAL FLOWS WITH THE UPS CODE.

Period of Performance: 01/01/1990 - 12/31/1990

$50K

Phase 1 SBIR

Recipient Firm

Applied & Theoretical Mechanic
4501 Sequoyah Road
Oakland, CA 94605
Principal Investigator
Firm POC

Abstract

THE PROPOSED WORK WILL IMPROVE THE ABILITY OF TURBULENCE MODELS TO SOLVE TRANSITION AND TURBULENCE PHENOMENA IN THE HYPERSONIC REGIME. THE STATE OF THE ART, UPS COMPUTER CODE,DEVELOPED AT NASA-AMES RESEARCH CENTER BY LAWRENCE ET AL. (1987), WILL BE THE BASIC NUMERICAL TOOL. TWO-EQUATION TURBULENCE MODELS, UPGRADED BY A TRANSITION MODEL, WILL BE INCORPORATED INTO THE UPS CODE IN A "LOOSELY" COUPLED MANNER. THE TRANSITION MODEL WILL BE BASED UPON THE PRODUCTION TERM MODIFICATION (PTM) DEVELOPED BY SCHMIDT AND PATANKAR (1987) FOR LOW SPEED FLOWS, AND WILL BE EXTENDED TO HYPERSONIC FLOWS. THE TRANSITION MODEL WILL DETERMINE ONSET AND END OF TRANSITION, NO SUCH HYPERSONIC TRANSITION MODEL EXISTS AT THE PRESENT TIME. THE PTM TECHNIQUE INCLUDES TWO CONSTANTS THAT WILL BE ADJUSTED USING EMPIRICAL CORRELATIONS FOR ONSET AND END OF TRANSITIONFOR HYPERSONIC FLOWS OVER CONES. THE MODEL WILL BE TESTED USING TRANSITION EXPERIMENTS FOR HYPERSONIC FLOWS OVER CONESAT MACH 6 AND 8, AND TO PREDICT TRANSITION PROCESSES FOR FLOWS OVER A CONE AT AN ANGLE OF ATTACK.