A ZONAL METHOD FOR MODELING POWERED-LIFT AIRCRAFT FLOW FIELDS

ADVANCED SHORT TAKEOFF/VERTICAL LANDING AIRCRAFT ARE DESIGNED TO USE EXHAUST JETS DIRECTLY TO INCREASE LIFT. BEING ABLE TO MODEL NUMERICALLY THE FLOW FIELDS INVOLVED IN THESE DESIGNS WOULD GREATLY IMPROVE THE DESIGN PROCESS. THIS PROJECT WILL DEVELOP A COST-EFFECTIVE FLOW ANALYSIS TOOL FOR MODELING POWERED-LIFT AIRCRAFT FLOW FIELDS. A KEY INGREDIENT IN THE DEVELOPMENT OF A PRACTICAL FLOW ANALYSIS IS THE TURBULENCE MODEL. THE PHASE I OBJECTIVE IS TO DEVELOP AND VALIDATE A TURBULENCE MODEL THAT WILL ACCURATELYAND EFFICIENTLY MODEL THE TURBULENCE PHENOMENA IN FLOWS WITHTHE STRONG CURVATURE ENCOUNTERED IN POWERED-LIFT FLOWS. A TWO-EQUATION MODEL COUPLED TO AN ALGEBRAIC REYNOLDS STRESS MODEL WILL BE INVESTIGATED IN THE CONTEXT OF A THREE-DIMENSIONAL NAVIER-STOKES CODE. A SUB-GRID-SCALE MODEL WILL ALSO BE EXAMINED. THE MODELS WILL BE TESTED BY CALCULATING A JET IN GROUND EFFECT WITH A CROSSFLOW WITH PARTICULAR ATTENTION ON THE GROUND VORTEX. ADVANCED SHORT TAKEOFF/VERTICAL LANDING AIRCRAFT ARE DESIGNED TO USE EXHAUST JETS DIRECTLY TO INCREASE LIFT. BEING ABLE TO MODEL NUMERICALLY THE FLOW FIELDS INVOLVED IN THESE DESIGNS WOULD GREATLY IMPROVE THE DESIGN PROCESS. THIS PROJECT WILL DEVELOP A COST-EFFECTIVE FLOW ANALYSIS TOOL FOR MODELING POWERED-LIFT AIRCRAFT FLOW FIELDS. A KEY INGREDIENT IN THE DEVELOPMENT OF A PRACTICAL FLOW ANALYSIS IS THE TURBULENCE MODEL. THE PHASE I OBJECTIVE IS TO DEVELOP AND VALIDATE A TURBULENCE MODEL THAT WILL ACCURATELYAND EFFICIENTLY MODEL THE TURBULENCE PHENOMENA IN FLOWS WITHTHE STRONG CURVATURE ENCOUNTERED IN POWERED-LIFT FLOWS. A TWO-EQUATION MODEL COUPLED TO AN ALGEBRAIC REYNOLDS STRESS MODEL WILL BE INVESTIGATED IN THE CONTEXT OF A THREE-DIMENSIONAL NAVIER-STOKES CODE. A SUB-GRID-SCALE MODEL WILL ALSO BE EXAMINED. THE MODELS WILL BE TESTED BY CALCULATING A JET IN GROUND EFFECT WITH A CROSSFLOW WITH PARTICULAR ATTENTION ON THE GROUND VORTEX.