Accession Number : ADA186215

Title :   Effects of Turbulence on Stationary and Non-Stationary Processes in C-Systems.

Descriptive Note : Final technical rept. 1 Sep 85-30 Nov 86,

Corporate Author : ILLINOIS UNIV AT URBANA DEPT OF AERONAUTICAL AND ASTRONAUTICAL ENGINEERING

Personal Author(s) : Roberts, Ted A ; Beddini, Robert A

PDF Url : ADA186215

Report Date : 01 Jun 1987

Pagination or Media Count : 36

Abstract : Turbularization of an acoustic boundary layer (Stokes Layer) on impermeable and permeable surfaces is analytically considered. The theoretical approach uses a second-order closure model of turbulence. Both an approximate, closed-form solution and a more comprehensive finite difference solution of the time dependent, parabolic, one-dimensional governing equations are obtained. For simple acoustic boundary-layers on impermeable surfaces, both the approximate solution and the numerical results for the critical acoustic Mach number required for turbulent transition are qualitatively confirmed by experiment. Calculations for acoustic boundary-layers with transpiration (injection) indicate a substantial reduction of the acoustic Mach number required for transition, up to a limiting injection velocity that is frequency dependent. The results may provide a mechanism for flow-related combustion instability in practical systems, particularly solid propellent rockets, since turbularization of the near-surface combustion zone could result at relatively low acoustic Mach numbers. This report documents a completed phase of work which is concerned with the analysis of turbulent flow and heat transfer behavior in rocket chamber flows (C-systems). Keywords: Acoustic instability; Aeroacoustics; Solid propellent rocket engines; Transpiration; Turbulent boundary layer; Acoustic boundary layer; Combustion instability; Laminar boundary layer.

Descriptors :   *COMBUSTION STABILITY, *TURBULENT BOUNDARY LAYER, ACOUSTICS, AERODYNAMICS, BOUNDARY LAYER, TIME DEPENDENCE, COMBUSTION CHAMBERS, CHAMBERS, COMBUSTION, EQUATIONS, FINITE DIFFERENCE THEORY, FLOW, HEAT TRANSFER, INJECTION, LAMINAR BOUNDARY LAYER, LAYERS, LIMITATIONS, MACH NUMBER, METHODOLOGY, NUMERICAL ANALYSIS, PERMEABILITY, ROCKETS, SOLID PROPELLANT ROCKET ENGINES, SOLUTIONS(GENERAL), STABILITY, SURFACES, THEORY, TRANSITIONS, TRANSPIRATION, TURBULENCE, TURBULENT FLOW, VELOCITY

Subject Categories : Combustion and Ignition
      Fluid Mechanics
      Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE