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-   -   Roughness has no influence on results, k-epsilon (http://www.cfd-online.com/Forums/cfx/77045-roughness-has-no-influence-results-k-epsilon.html)

Robert Safar June 11, 2010 03:12

Roughness has no influence on results, k-epsilon
 
I try to modelling flow over a small dam (embankment). The rougness of dam surface is about d90=20mm (grain size). I tried to model smooth wall and rougnesses hs= 0, 10, 20, 30, 40, 50 mm.
In this case i have these problems:
1. different results between smooth wall and rough wall hs=0mm
2. For rougneses hs higher than 20 mm is no influence on results (water level - head is constant)

Robert Safar June 14, 2010 07:21

1. There was a problem with mesh thickness.
2. Ok it's my fault. I didnt know that the first cell of mesh must be twice higher than rougness.


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