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Old 10-21-2020, 10:50 AM   #5 (permalink)
aerohead
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'free' software

Quote:
Originally Posted by freebeard View Post
Whelp, they're both gone; but both right? Or they agree and they're both wrong?

CFD is useful. The problem is in the software. The big corps throw money at the problem that 'free' software won't resolve. But computational science progresses. It's a modeling problem. The memory and speed constrained solutions are obsolete.

https://en.wikipedia.org/wiki/OpenVDB

https://www.openvdb.org/




I know what they are saying, but I couldn't say it as well myself. I used to work elbow-deep in the MacOS file structure, so I have an understanding of sparse, shallow b-trees. They use some brilliant optimizations.

So what does this mean for the unwashed masses? It has to do with free and open-source software. The best, fastest moving example I know of is Blender. It evolves on a rapid schedule, but with landmark long-term support releases so you can plan forward:


Blender has a physics engine and OpenVDB support. Here's a demonstration of it's use:

https://www.blendernation.com/2020/0...db-quickstart/

Blender itself has implemented adaptive subdivision which works on similar principles.



A CFD demo reel is above my pay grade, although I understand the principles, I lack the muscle motor memory. I hit a wall early on. But there's your solution — free, runs on low-end hardware but likes big iron.
'Commercial / Industrial' CFD competes with full-scale wind tunnels.
Their 'price-point' must be 'competitive' in the marketplace.
If using, say, Dassault's EXA POWERFLOW CFD ( which Tesla Motors used for their Model S development ) can produce output in 48-hours, equal to, and at a cost advantage to full-scale wind tunnel testing, then there's a probability that it will be seen as smart business decision.
If it costs $ 2,000 / day (perhaps the minimum ), it's the same cost as 1/2-hour of wind tunnel time.
And since it requires a supercomputer, or, say, 100 desktops running in parallel, we might not expect 'free' software to offer the degree of realism the 'big-boys and girls' are obtaining.
The CFD Daimler- Benz and BMW use is 99% accurate, compared to 1:1-scale wind tunnel testing.
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