# LES pipeflow dynOneEddy strange results

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 June 7, 2014, 05:40 LES pipeflow dynOneEddy strange results #1 Member   Florian Ries Join Date: Feb 2014 Location: Darmstadt, Germany Posts: 88 Rep Power: 5 Hi all, I've done some LES simulations of pipeflow with dynOneEddy-Model and compare my results with oneEddy-Model and WALE model. I get some strange results for ksgs -> nuSgs. first some informations: 1) problem description - pipe diameter 0.04m - length of the pipe 4*D (cyclic Boundary conditions) - fluid water nu=1.081e-06 - incompressible flow Re=4900, Retau=340 - Grid: structured O-Grid r+ wall = 2,5 r+ mean = 7.5 z+ = 35 eta+ = 10 I have also used finer grid and I have the same problem (problem see below) 2) Boundary conditions: ---k , p , nuSgs--- boundaryField { inlet { type cyclic; } outlet { type cyclic; } pipewall { type zeroGradient; } } ---U --- boundaryField { inlet { type cyclic; } outlet { type cyclic; } pipewall { type fixedValue; value uniform (0 0 0); } } 3) Schemes/Solution/Options - I used pressureGradientExplicitSource to get the cyclic flow. - all schemes Gauss linear or Gauss linear corrected - ddtSchemes: backward - pimple with residual control U,p<10^-5, k<10^-7 - initalize the U-field fully turbulent by mapping data from other simulation - fieldAverage 200D The velocity profiles in u+ y+ looks ok for all models (dynOneEddy is ok but the others are better). But in dynOneEddy-model I get strange behavour for nuSgsmean and kSgsmean. --------- Here my results for nuSgsmean over 200D---------- 1. WALE: SmagNuSgsmean.jpg looks good. At the wall, nuSgs decrease because of WALE model. NuSgs is smooth ober the domain 2. OneEddy OneNuSgsmean.jpg results looks reasonable, because I do not use van Driest damping at the wall and it is not a dynamic procedure implemented. But nuSgs is smooth. 3. dynOneEddy dynOneNuSgsmean.jpg looks not good!! Why these two stripes??? ------ Here my results for kSgsmean------------- 1. OneEddy OnekSgsmean.jpg looks reasonable, because no dynamic procedure implemented. 2. dynOneEddy dynOnekSgsmean.jpg puuh, What's going on at the wall?? What about these two stripes again?? In dynOneEddy-model the results for nuSgsmean and kSgsmean looks strange. First I thought it is the grid. But even with finer grid I get the same results. For Smagorinsky, dynamicSmagorinsky, WALE, OneEddy-model I get with this mesh, bc etc. good results. Whats wrong with dynOneEddy-model??? Is there a fault in the implementation of the dynamic procedure in dynOneEddy-model?? Somebody an idea??? kind regards Florian

 June 9, 2014, 12:59 #2 Member   Florian Ries Join Date: Feb 2014 Location: Darmstadt, Germany Posts: 88 Rep Power: 5 Hi, is there somebody with experience with dynOneEddy-Model???? kind regards Florian

March 15, 2017, 02:47
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zhaoshiyu
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Quote:
 Originally Posted by itchy Hi, is there somebody with experience with dynOneEddy-Model???? kind regards Florian
Did you finish this problem
I also have some problems using this scheme

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