Large eddy simulation for flow around cylinder

ash_kul999 · April 15, 2015, 07:15

Hello all,
I want to perform Large Eddy Simulation for flow around 2D circular cylinder.Fluid medium is water and the diameter of cylinder is 0.1m. I am using PISOFoam solver. I had tried the simulation many a times by changing various parameters in the solver. I could visualize the flow in the paraFoam but when it comes to validation part, the values of coefficient of drag,lift and moment are wrong (in the order of 1e10).I am not able to fix this problem. Can anyone suggest me what could be the reasons behind this? If possible please send me benchmark test case setup file.

thanks,
Ashish

rama13 · April 15, 2015, 09:01

Hi Ashish,

please find in attachment two different cases of flow around cylinder at Re=2*1e6, one using RANS and one with LES, both with pisoFoam.

Results are obviously not the same -they have runned on the same mesh-, but at least they share the same order of magnitude!

Hope this helps,
Damiano

cL.jpg

cD.png

LES.zip

RAS.zip

ash_kul999 · April 15, 2015, 13:11

Thanks a lot sir!!! I will compare with this set up and do the correction. I will post my further queries and results here.

ash_kul999 · April 17, 2015, 17:06

Sir,
I am having trouble with swak4foam while installing. what is the exact role of it in this simulation? can we perform LES without swak4foam?

rama13 · April 18, 2015, 04:02

Sure, you have to comment out some functions in the system/controlDict

Bests,
Damiano

ash_kul999 · April 18, 2015, 04:47

Sir,
I have installed swak4foam. The test case is running fine.But unlike my previous simulations I am not getting forceCoeffs.dat file in the postprocessing folder. How to get the vlaues of Cd,Cl and Cm i the results?

April 15, 2015, 07:15	Large eddy simulation for flow around cylinder	#1
ash_kul999 New Member ashish kulkarni Join Date: Mar 2015 Posts: 4 Rep Power: 11	Hello all, I want to perform Large Eddy Simulation for flow around 2D circular cylinder.Fluid medium is water and the diameter of cylinder is 0.1m. I am using PISOFoam solver. I had tried the simulation many a times by changing various parameters in the solver. I could visualize the flow in the paraFoam but when it comes to validation part, the values of coefficient of drag,lift and moment are wrong (in the order of 1e10).I am not able to fix this problem. Can anyone suggest me what could be the reasons behind this? If possible please send me benchmark test case setup file. thanks, Ashish

April 15, 2015, 09:01	Large eddy simulation for flow around cylinder	#2
rama13 New Member Damiano Natali Join Date: Mar 2013 Location: Genova, Italy Posts: 17 Rep Power: 13	Hi Ashish, please find in attachment two different cases of flow around cylinder at Re=2*1e6, one using RANS and one with LES, both with pisoFoam. Results are obviously not the same -they have runned on the same mesh-, but at least they share the same order of magnitude! Hope this helps, Damiano cL.jpg cD.png LES.zip RAS.zip __________________ Damiano Natali Eng Phd \| R&D and FEA Engineer ________________________________________ Cressall \| Optimum Resistor Solutions Evington Valley Road, Leicester, Leicestershire, LE5 5LZ, UK. NERs \| Load Banks \| Marine & Offshore \| DBRs \| Renewables

April 18, 2015, 04:02		#5
rama13 New Member Damiano Natali Join Date: Mar 2013 Location: Genova, Italy Posts: 17 Rep Power: 13	Sure, you have to comment out some functions in the system/controlDict Bests, Damiano __________________ Damiano Natali Eng Phd \| R&D and FEA Engineer ________________________________________ Cressall \| Optimum Resistor Solutions Evington Valley Road, Leicester, Leicestershire, LE5 5LZ, UK. NERs \| Load Banks \| Marine & Offshore \| DBRs \| Renewables

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April 15, 2015, 13:11		#3
ash_kul999 New Member ashish kulkarni Join Date: Mar 2015 Posts: 4 Rep Power: 11	Thanks a lot sir!!! I will compare with this set up and do the correction. I will post my further queries and results here.

April 17, 2015, 17:06		#4
ash_kul999 New Member ashish kulkarni Join Date: Mar 2015 Posts: 4 Rep Power: 11	Sir, I am having trouble with swak4foam while installing. what is the exact role of it in this simulation? can we perform LES without swak4foam?

April 18, 2015, 04:47		#6
ash_kul999 New Member ashish kulkarni Join Date: Mar 2015 Posts: 4 Rep Power: 11	Sir, I have installed swak4foam. The test case is running fine.But unlike my previous simulations I am not getting forceCoeffs.dat file in the postprocessing folder. How to get the vlaues of Cd,Cl and Cm i the results?