Re: CFD for can design.
I don't know of a cheap CFD software, but wouldn't worry about it.
CFD does not work very well for projecting suppressor performance. We did integrate CFD into R&D at one point and tested past designs and found that while CFD initially looked promising, it simply wasn't an accurate and reliable indicator of performance.
What it will do is waste weeks of time doing 3-4 hour simulations on dozens of models. A few hundred hours of CFD will wear out a hard drive- the calculations require a lot of processing power.
It will give you a basic idea of what gas will do in your design, but just doesn't help as much as anyone would expect from the outside looking in.
This of course would be totally different if you could accurately simulate the moving bullet and dynamically simulate the still burning powder/expanding gas inside the virtual suppressor, but I'm not sure that is a capability that exists currently.
This isn't my sole opinion. It is shared by many industry people. The suppressor industry is also sometimes lame in that people will pretend that the technology they integrate into design makes their product the must have product, so don't expect honesty from all sides- I'm sure some marketing whore wants to suggest that CFD is the be all, end all.
Unfortunately the best way to design suppressors is to make designs, and test them to confirm or deny improved performance, modifying them slightly through multiple evolutions to reach the desired performance objective. This is why industry suppressors are a better value than they may appear to people who see them as things they can build something similar to for $150. If you have to buy a meter, and separately design and build 10-20 of them to get one equaling the performance of the industry product, you're now into it $1500-$3000 in material, $3000 in a meter, and several months of unpaid labor. The human ear can't accurately tell you when something improved 2-3DB, so without the meter, developing a product would be very difficult.
