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CFD grid/mesh independence analysis

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Old   April 25, 2018, 05:24
Unhappy CFD grid/mesh independence analysis
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Jack
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Hello group! I am new to CFD and I would like your help regarding a problem I have. I have a microfluidic channel and I would like to make the grid/mesh independence analysis. I have meshed the fluid domain using brick elements and I started with 1 to 0.2 μm element size. I have put some monitoring points inside the fluid domain to track the pressure and the velocity values at some points. I first start my analysis using the Convergence Criteria set to be RMS with Residual Target 1e-4. But the monitoring points didn't reached a constant value. So, I changed it and I tried different values. Finally, I found out that using 1e-10 was the best Residual target for me. The problem is that during the mesh analysis and making the mesh more finer, the values of the monitoring points don't reach a constant value and they keep increasing. Why is that happening ?
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Old   April 25, 2018, 08:12
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Glenn Horrocks
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Your simulation may be more sensitive to convergence on imbalances than residuals. What is the imbalances for these simulations?

Also - please explain what you are modelling and some an image so we can understand your application.
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