EXTENSION

ABLATION BEHAVIOR AND THERMAL PROTECTION REQUIREMENTS FOR REENTRY VEHICLES ARE SIGNIFICANTLY INFLUENCED BY ROUGH WALL CONVECTION EFFECTS. TO ACCURATELY CHARACTERIZE THE EFFECTS FOR SYSTEM DESIGN, IT IS ESSENTIAL TO UNDERSTAND THE PHYSICS OF THE TURBULENT BOUNDARY LAYER SUBJECT TO ARBITRARY ROUGHNESSES, AND THE ABLATION INDUCED DEVELOPMENT OF THE MORPHOLOGY. PHASE I OF THIS PROGRAM WILL ADDRESS THE BOUNDARY LAYER PHYSICS ASPECTS OF THE TECHNOLOGY. RECENT WIND TUNNEL SIMULATION DATA WILL BE REVIEWED AND ANALYZED FOR THE PURPOSES OF BRINGING THE RESULTS INTO THE EXISTING DATA BASE ENCOMPASSED BY THE CORRELATIONS EXISTING IN THE ABRES SHAPE CHANGE CODE (ASCC). TO FACILITATE DATA CORRELATIONS, FUNDAMENTAL BOUNDARY LAYER MODELING STUDIES WILL BE CARRIED OUT TO EXAMINE THE EFFECTS OF SURFACE MORPHOLOGY ON THE THERMAL AND MASS BOUNDAY LAYERS. WHEREAS THE IDEA OF AN EQUIVALENT SAND GRAIN ROUGHNESS HAS BEEN SHOWN TO CHARACTERIZE THE BEHAVIOR OF THE MOMENTUM BOUNDARY UNDER MOST CONDITIONS, THE PROPOSED RESEARCH HAS AS AN OBJECTIVE THE DERIVATION OF A THERMAL OR MASS BOUNDARY LENGTH SCALE OR RELATED FIGURE OF MERIT THAT CAN BE USED IN CONJUNCTION WITH THE EQUIVALENT SAND GRAIN ROUGHNESS TO CHARACTERIZE THE COUPLED MOMENTUM AND THERMAL OR MASS BOUNDAY LAYERS THAT DICTATE CONVECTIVE TRANSFER.