Im gonna go with John on this one. Fluid stuff was good back in the day but you can't beat the math. Fluid acts differently under teh same circumstances then air does. IE: Doesn't expand as much under heat, doesn't compress as well, and doesn't dissipate heat at the same rate. All of this can be calculated to a certain extent but just isn't as effective as the computer generated maps done today.

-- PS. My back hurts like hell. Kbye.