k-epsilon model and simpleFoam
I have a few questions about model, I applied it to an airfoil (blade section of a marine propeller). I based myself on pitzDailyExptInlet tutorial.
1. why is turbulenceProperties file not included? 2. tutorial nut and nuTilda are set on zero. I used this configuration, is it correct? Here I read that nuTilda is superfluous, is it the same with nut? I'm confused, in tutorials fvschemes and fvSolution files I find nuTilda (and not nut). 3. in tutorial R file I read Code:
upperWall Code:
value uniform (0 0 0 0 0 0); |
Hi, I got few answers for you:
ad 2> nut is turbulent viscosity for incompressible flows, mut is dynamic turb. viscosity used for compressible or heat transfer flows. nuTilda is only for Spalart-Allmaras model. Therefore for k-eps model you need only nut or mut. try to remove all of them and the code will tell you which one is missing. in fvSchemes and fvsolution you need the variables accordingly The wall functions are defined here in sedction RAS wall functions ad 3> R is reynolds stress tensor and you do not need to set anything, look at $FOAM/src/turbulenceModels/incompressible/RAS/kEpsilon/kEpsilon.C lines 140 to 160 and what you see is, that the R field is calculated internaly and is not read at all, so there is no point to set this file at all in your 0/ directory. good luck matej |
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Please, help me. I'm in trouble with and simpleFoam. Lift and drag coefficients are enormous and too. I can't understand the problem, I refined and refined (and refined again) the mesh, but nothing really changed (and I use wall functions). I evaluated initial values for and as in ESI guidelines:
= 0.01 = 0.005 with = 7.3 m/s = 1% = 1 and dynamic viscosity = 1.22e-3 I hadn't this terrible result with or Spalart-Allmaras turbulent models (obviously with different meshes), I can't understand that. Maybe it' a problem about my BC or fvSchemes and fvSolution files. Can anyone help me? See the attached files, please. I can't manage alone. |
hi
i didnt want to open a new topic so i state my question here. i am simulating a turbulent incompressible flow with simpleFoam and the kEpsilon model. i want to take a look at the Reynolds Stress Tensor. how can i make simplefoam to display it? i know that the tensor must be calculated and i would like to see the result :) regards //edit i found the function R wich calculations the reynolds stress tensor at a given time step. now i have an R file with the numbers, alot of numbers *g* thx anyway ;) |
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