Accession Number : AD0635154

Title :   MOMENT METHODS IN RADIATIVE TRANSFER PROBLEMS.

Descriptive Note : Technical information series.

Corporate Author : GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV

Personal Author(s) : Sherman, M. P.

Report Date : JUN 1966

Pagination or Media Count : 42

Abstract : Half of the equations obtained from the radiative transfer equation by use of any moment approximation are unstable. Small changes in choice of the unknown boundary values give rise to large changes in the solution. In this work the cause of this difficulty is isolated and the problem overcome. The techniques developed give new insight into the moment approximations. The complex boundary conditions derived by Krook (On the Solutions of the Equations of Transfer I, Astrophy J.122:1955) for the full moment approximations have a simple meaning in transformed variables. A comparison is made of the accuracy of full and half moment approximations using several examples. The first full moment (Eddington) approximation is found roughly comparable to the first half moment approximation, the second full moment to the second half moment approximation. (Author)

Descriptors :   (*TRANSPORT PROPERTIES, NUMERICAL ANALYSIS), DIFFERENTIAL EQUATIONS, FLUID MECHANICS, BOUNDARY VALUE PROBLEMS

Subject Categories : Numerical Mathematics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE