Accession Number : AD0872901

Title :   A Study of the Modal Response Approach to Patterned Ablation Including Experiment Definition.

Descriptive Note : Final technical rept. 15 Jan 69-30 Apr 70,

Corporate Author : AERONAUTICAL RESEARCH ASSOCIATES OF PRINCETON INC NJ

Personal Author(s) : Conrad, Peter ; Donaldson, Coleman duP. ; Snedeker, Richard

Report Date : APR 1970

Pagination or Media Count : 128

Abstract : Patterned ablation is hypothesized to be caused by a resonance or tuning response of the boundary layer to small disturbances originating at the wall from surface irregularities. An inviscid linear theoretical approach has been developed which approximates the boundary layer by many layers of uniform compressible flow and computes the pressure response at the wall. Using this, together with a simplified analysis of the ablation process, a mechanism for pattern geometry selection is shown. In addition, a second more rigorous theoretical approach is developed which treats the effects due to viscosity, turbulence and mass injection. Finally an experimental program, consisting of a series of gas-dynamically scaled ablative tests on geometrically similar cones, is proposed in order to determine if patterns can be produced due to purely gas dynamic phenomena. (Author)

Descriptors :   (*ABLATION, THEORY), BOUNDARY LAYER, RESPONSE, SURFACE PROPERTIES, COMPRESSIBLE FLOW, MATHEMATICAL ANALYSIS, VISCOSITY, TURBULENCE, CONICAL BODIES, DYNAMICS, NOSE CONES, RESONANT FREQUENCY, PRESSURE, WALLS, MASS TRANSFER, INJECTION, TURBULENT BOUNDARY LAYER, MATHEMATICAL MODELS, EXPERIMENTAL DESIGN.

Subject Categories : Guided Missile Traj, Accuracy and Ballistics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE