Accession Number : AD0874560

Title :   Investigations of Ablation Surface Cross-Hatching.

Descriptive Note : Final rept. 11 Jun 69-Jun 70,

Corporate Author : MCDONNELL DOUGLAS ASTRONAUTICS CO-HB HUNTINGTON BEACH CA

Personal Author(s) : Williams, Edgar P. ; Inger, George R.

Report Date : JUN 1970

Pagination or Media Count : 201

Abstract : The Ablation-Surface Cross-Hatching Program is one of several programs directed toward understanding and suppressing cross-hatched patterns on ablating surfaces. It consists of two wind tunnel studies with analyses which are reported herein: First, an investigation of the phasing of the pressure and temperature distributions over a two-dimensional nonablating wavy wall confirmed in-house theoretical predictions. It is believed this is the first time that heat transfer and insulated wall temperature phasing correspondence to pressure in the cross-hatching process has been theoretically proved and experimentally confirmed. An unexpected cusping of pressure was found at transonic speeds. Second, hypersonic wind tunnel tests, including six-component force measurements, of conical camphor and Korotherm models extended the cross-hatching angle versus edge Mach number correlation; showed nose tip bluntness effects compatible with this correlation and showed that roll torques produced as a result of windward meridian shift after pattern formation are stable. A pre-cross-hatched nonablating model confirmed cross-hatching experience by indicating higher heat transfer to the valleys than to the ridges.

Descriptors :   (*ABLATION, SURFACE PROPERTIES), AERODYNAMIC CONFIGURATIONS, WALLS, NOSE CONES, CONICAL BODIES, SURFACE TEMPERATURE, HEAT TRANSFER, TURBULENT BOUNDARY LAYER, AERODYNAMIC LOADING, PRESSURE, ROLL, CRYSTALS, LIQUIDS, REFRACTORY COATINGS, COOLING, PRANDTL NUMBER, TRANSONIC FLOW, HYPERSONIC FLOW, WIND TUNNEL MODELS, INSTRUMENTATION, ANGLE OF ATTACK, MOMENTS, AERODYNAMIC CHARACTERISTICS, AERODYNAMIC HEATING, MODEL TESTS.

Subject Categories : Guided Missile Dynam, Config & Cntrl Surfaces

Distribution Statement : APPROVED FOR PUBLIC RELEASE