numerical diffusion & patch operation

ronen · April 10, 2011, 02:02

1. What are the options available to avoid numerical diffusion?

2. When I patch a small volume I get an avaraged value of the specified parameter at the marginal grid of the volume. How can I avoid it?

Thx

Amir · April 10, 2011, 09:57

it doesn't occur if you display cell values not node values. (you can set that in display->contour)

ronen · April 10, 2011, 12:17

Thx for the quick replay, the tip helped and works

What about the Numerical diffusion? The mesh is refined and the results are still exhibit significant false diffusion which is beyond the resonable for the mesh size. What can I do about that?

Amir · April 10, 2011, 12:25

Quote:

Originally Posted by ronen

Thx for the quick replay, the tip helped and works

What about the Numerical diffusion? The mesh is refined and the results are still exhibit significant false diffusion which is beyond the resonable for the mesh size. What can I do about that?

I just know that some numerical algorithms and schemes have numerical diffusion behavior because of their definitions, if you describe your problem clearly, I may help you.

ronen · April 10, 2011, 17:44

I managed to perform LES(Smagorinsky-Lilly).
Now I would like to model species transport.

April 10, 2011, 02:02	numerical diffusion & patch operation	#1
ronen New Member ronen Join Date: Apr 2011 Posts: 7 Rep Power: 15	1. What are the options available to avoid numerical diffusion? 2. When I patch a small volume I get an avaraged value of the specified parameter at the marginal grid of the volume. How can I avoid it? Thx

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April 10, 2011, 09:57		#2
Amir Senior Member Amir Join Date: May 2009 Location: Montreal, QC Posts: 735 Blog Entries: 1 Rep Power: 22	it doesn't occur if you display cell values not node values. (you can set that in display->contour)

April 10, 2011, 12:17		#3
ronen New Member ronen Join Date: Apr 2011 Posts: 7 Rep Power: 15	Thx for the quick replay, the tip helped and works What about the Numerical diffusion? The mesh is refined and the results are still exhibit significant false diffusion which is beyond the resonable for the mesh size. What can I do about that?

April 10, 2011, 17:44		#5
ronen New Member ronen Join Date: Apr 2011 Posts: 7 Rep Power: 15	I managed to perform LES(Smagorinsky-Lilly). Now I would like to model species transport.