Acceleration techniques for the radiative analysis of general computational fluid dynamics solutions using reverse Monte-Carlo ray tracing

A reverse Monte-Carlo ray trace capable of performing a radiative analysis on arbitrary multiple overlapping structured computational fluid dynamics solution sets is developed. In order to make effective use of time, a method based on a set of simplifying assumptions but using the same calculation procedures is developed for comparison and study purposes.

Three acceleration techniques are tried. One acceleration technique reduces the grid dimensions to reduce the number of volumes intersected. The second acceleration technique develops a version of the code for execution in a parallel processing environment. The third acceleration technique mixes an orthogonal, evenly spaced grid with the computational fluid dynamics grids to obtain fast ray traversal of low variance areas while retaining the higher resolution of the computational fluid dynamics grids in the high variance areas.

Two experimental data sets are used for comparison and as test cases during these studies: an exhaust plume from an auxiliary power unit, and a Boeing 747 in flight. Timing for the baseline and accelerated analyses is provided as well as numerical comparisons for a selected subset.