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using artifical diffusion
Posted 2010/06/16 8:39 GMT-4 2 Replies
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hello there. i just want to ask is that, if our problem of fluid dynamics is converging without using any artifical diffusion then is it ok? or do we need to apply artifical diffusion at all cost. My problem is converging without applying artifical diffusion and when i apply artifical diffusion it starts giving me some problems.
Regards.
Yasir
Regards.
Yasir
2 Replies Last Post 2010/06/17 8:59 GMT-4
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Posted:
1 decade ago
same question here.
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Posted:
1 decade ago
Hi, just because it converged doesn't mean it converged to the "best" answer...! If you have very high shock waves, then you might get a lot of ringing without articifial diffusion. You'd probably prefer to have those oscillations damped even if that means you are solving a slightly different equation. On the other hand, adding it might be blurring out some event that you do want to see.
A simple way to gain confidence in your solution is to refine the mesh more (maybe a lot more), zoom in visually to any regions of high changes in velocity, and check that the answer was the same as before mesh refinement. If it is still converging and if it is converging to the same answer then it sounds like you don't want, or need, artificial diffusion.
Regards, John
A simple way to gain confidence in your solution is to refine the mesh more (maybe a lot more), zoom in visually to any regions of high changes in velocity, and check that the answer was the same as before mesh refinement. If it is still converging and if it is converging to the same answer then it sounds like you don't want, or need, artificial diffusion.
Regards, John