Arragonis -
The "safe" bitmap size is 256x128. If I were you, I would make a 256x128 2-bit (black and white) bitmap. These are the rules I followed in my image :
(JPEG for browser visibility)
In terms of inputs, I use these :
Re = 2500000 (calculated for about 55mph)
dt = 0.01
length = 40sec
cutoff level = 40
Other than the time length, the inputs have been debated a lot, so I don't know if they are the right ones. IMO they do make the flow "more granular". Also, the 40 seconds allows the flow to stabilize.
CarloSW2