numerical diffusion & patch operation
 

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 :)

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

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.

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