Averaging of radiation transfer equations in two-dimensional radiation gasdynamic problems

Various methods for averaging radiation transfer equations in two-dimensional non-steady-state radiation gasdynamic problems are examined. Attention is given to the frequency averaging of the differential transfer equation, its difference analog, and integral transfer equation. Limiting transitions to optically thick and optically thin volumes are analyzed. In addition to the cases where the transfer equation is integrated along a certain set of rays, a method is analyzed whereby angle averaging is performed, this method being the two-dimensional analog of the mean flow method. For a specific two-dimensional problem concerning the propgation of a supersonic radiation wave, a field of characteristic directions for the integration of angle-averaged radiation fluxes is given. Ways to improve the efficiency of averaging are discussed.