
Accession Number : AD0684571
Title : AN APPROXIMATE METHOD FOR ANALYZING NONEQUILIBRIUM ACOUSTIC PHENOMENA WITH APPLICATION TO DISCRETE RADIATIONDRIVEN WAVES,
Corporate Author : STANFORD UNIV CALIF DEPT OF AERONAUTICS AND ASTRONAUTICS
Personal Author(s) : Cogley,Allen C.
Report Date : FEB 1968
Pagination or Media Count : 267
Abstract : A study is made of the interaction between radiative heat transfer and fluid flow in the acoustic approximation. The work introduces a new analytical technique for handling onedimensional radiative transfer in a nongrey gas near equilibrium. Radiative effects are treated on the basis of the quasiequilibrium hypothesis, and for simplicity the gas is assumed to be perfect. A nongrey exponential approximation is made to obtain a differential formulation. Combination of the resulting simplified transfer equation with the gasdynamic equations gives a fifthorder partial differential equation in a perturbation potential. An approximate mathematical method for solving linear wavepropagation problems in the presence of nonequilibrium processes is then employed. The solutions of several previously considered problems are obtained with this approach. The previously unsolved problem of the gasdynamic response to a step input of radiation from a stationary black wall has also been solved. As shown by the solution, the radiative transfer gives rise initially to a compressionexpansion wave in the gas, with the wavefront controlled by radiation. The disturbance at the wavefront, though caused directly by radiative transfer of small time, eventually outruns the wall radiation and becomes a modifiedclassical disturbance propagating away from the wall at the isentropic speed of sound. (Author)
Descriptors : (*GAS FLOW, *THERMAL RADIATION), (*AERODYNAMICS, *ACOUSTICS), WAVE PROPAGATION, INTERACTIONS, MATHEMATICAL MODELS, APPROXIMATION(MATHEMATICS), PARTIAL DIFFERENTIAL EQUATIONS, ONE DIMENSIONAL FLOW, PULSES
Subject Categories : Acoustics
Fluid Mechanics
Thermodynamics
Distribution Statement : APPROVED FOR PUBLIC RELEASE