For the past 5 years I have been designing (in my spare time) and building prototypes for a gizmo (can't say more yet, sorry) I am currently on prototype 4, This prototype will cost me plenty of hard earned cash so instead of building a test tank and scaled models, I was wondering if anybody has come across a program to simulate fluid flow across a given shape? This would enable me to refine the form and build a better prototype! Any input would be highly appreciated. Thanks