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Serious problems to perform LES of the channel flow |
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April 29, 2012, 08:27 |
Serious problems to perform LES of the channel flow
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Laurent bricteux
Join Date: Apr 2012
Posts: 3
Rep Power: 14 |
Dear all,
I am trying to validate LES approach for openfoam on the turbulent channel flow at retau=395. The problem is that the results are far from that of the DNS reference. By inspecting some possibilities we decided to run the case with no model on an LES grid. The results shows that the code is hyper dissipative without any SGS model. Inspecting the u+ profile shows that it is completely above that of the DNS meaning an overediction of the debit. This is linked to the dissipation errors produced by the code. We tried a less severe case with two vortices in a box and no molecular viscosity. With the linear central scheme, this must conserve kinetoc energy for a while.... We lost 20%.... on the initial level. In these conditions, adding a SGS model will results in a deterioration of the results. I did not found relevant literature on this. Could someone help me? Nobody published LES performed with a state of the art model e.g. Wale model and showed good agreement with DNS data. We performed the DNS at lower Retau 180 and that works fine as it can be also found in literature. I am planning to use OF for LES in turbomachinery | engine applications. What if a simple turbulent flow between two plates cannot be predicted ? If someone can help I would appreciate |
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Tags |
channel flow, les |
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