Fluids

Fluids

FLUENT convergence

    • Dilini
      Subscriber
      Hello,nI am running a multi phase model in Fluent using K epsilon model. I have a question regarding model convergence. Before deciding mesh convergence,nI monitored the lift force (that is my quantity of interest as the output) and made sure it gets stable to one value for more than 50-100 iterations.nI checked the mass flow rate of inlet, outlet, sides, top (my domain is like a cube) and I got 100% mass conserved (both air and water)nI kept Fluent's default residual 0.001 value, but it was not converging much so I increased it to 0.002 to check and then it got converged.nAdditionally my results has a very good agreement with experimental results.nSo is it safe to assume that the modeling I did using FLUENT does a good job? I am slightly concerned since I changed the residual convergence criterion to 0.002. nPlease let me know.nThank you.nRegardsnDilinin
    • Surya Deb
      Ansys Employee
      Hello, nCan you please check which residual is not converging? Do all of them including mass, velocities, k, epsilon behave the same way or is it a few specific residuals which are harder to converge?nDo you see fluctuations in k or epsilon residuals during your run?nAlso please check your wall Y+ values to make sure that the k-epsilon model is being used properly in the proper Y+ ranges.nDid you also check with SSt k-omega type of a turbulence model?nAlso did you try using a Coupled Solver with a lower TSF (if running in steady state)?nRegards,nSuryann
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