Mesh Refinement
Hi everyone,
I used a mesh size which provided me the converged solution while resulting in the correct trend for monitoring quantities such as skin friction coefficient. But when I reduced the mesh by 10% of its previous cell size, the trend for the same quantity becomes quite random. I never expected this, since refinement has to go in favour of considerable accuracy. Any suggestions, why does this happen? Thanks for your time. Regards, |
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[QUOTE=CFDfan;779975]what software did you use?[/QUOTE
I used STARCCM+; |
Hi MA,
mesh refinement does not always lead to a more converged solution, such as in text book cases. Especially in turbulent cases, the resolvable flow features are determined by local mesh density. It can happen, that you have a domain, where a finer mesh will resolve more of flow features which might alter the simulated flow. The consequence could be a seemingly stable flow shifts to unstable/transient flow detaching. Having only two simulations with such a small density difference mesh seldom lead to sufficient confidence that you achieved a "good" solution. In general make at least 3 different simulations to assess whether these simulation can be assumed to be converged. Go further, if you haven't found a trustworthy solution. This is especially required in academic problems. Best regard, Sebastian |
[QUOTE=mazhar16823;779978]
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[QUOTE=CFDfan;780128]
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That could be a good reason but I wouldn't go for "further refinement" because it will bloat the cell count so I am making the farfield a little finer to achieve the fine mesh since the geometry has Y+ within 5. |
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