(Lite, Free; Wind Tunnel, $1.99; Pro, $2.99; Pro HD, $5.99; Lite for iPad, Free; iPad, $1.99; iPad Pro HD, $5.99) This dizzying array of products all have the same purpose: an aerodynamic testing simulation of a physical wind tunnel.
The options for visualization are impressive, and the feature-set is ambitious. I wish there were a way of importing artwork from an external source, and that you could create a Bezier-curve based drawing rather than "painted" sketches to create models, but it's all great fun.
I made this demonstration video to show some friends the app. The models are all mine, and the big titles were superimposed in another piece of video-editing software:
The higher-priced versions feature more visualization options, and the ability to load and save previously-made models.
(Wind Tunnel Lite for iPhone Free)
(Wind Tunnel for iPhone $1.99)
(Wind Tunnel Pro for iPhone $2.99)
(Wind Tunnel Pro HD for iPhone $5.99)