Over at the VizWorthWatching blog (run by some CEI staff), they have an article on an analysis of the underbody of the 1997 Camaro SS.  After establishing a baseline with a classic wind tunnel, the simulated the effect with StarCCM+, and then exported the data for use in EnSight.

Some nice pictures, with a few details on the process, over at their site.

Viz Worth Watching: Camaro Underbody Design.