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interFOAM LESModel Smagorinsky turbulent - Model Calibration |
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January 31, 2023, 03:28 |
interFOAM LESModel Smagorinsky turbulent - Model Calibration
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Steve
Join Date: Jun 2022
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Dear Openfoamers,
I would like to ask for your help I am using LES Smagorinsky model and interFoam to modelling 3D turbulent dynamic of a spillway. It run smoothly and stable. However, for calibration, which parameter should I adjust? 1. I adjusted the roughness of the model by creating a finer net. As a result, the model run very slowly because of enormous cells (3.8 million cells with a vertical cell size 60*mm). Meanwhile. the previous model consists of 400,000 Cells only with the vertical cell size 40cm 2. Then, I tried to use nutkRoughWallFunction in Nut file. It was defined as follow: /*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 5 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; location "0"; object nut; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 2 -1 0 0 0 0]; internalField uniform 1e-11; boundaryField { inlet { type zeroGradient; } outlet { type zeroGradient; } top { type zeroGradient; } rinne { type nutkRoughWallFunction; Ks uniform 0.006; Cs uniform 0.5; value $internalField; } } // ************************************************** *********************** // Note : Ks=(25.6/Kst)^6 = (25.6/60)^6 = 0.006 ( equivalent Concrete Wall) ; Kst: Strickler roughness = 1/n (n: Manning coefficient) The model was running a few minutes and was crashed due to a large Courant number, although the time step was very fine (10^-11). I also let the interFoam change the time step automatically but It didn't work What should I do to calibrate the model? Here is the link to model: https://drive.google.com/drive/folde...usp=share_link Many thanks in advance Best regards, Steve |
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