Setting up LES of Airfoil in OpenFoam

Jack001 · May 12, 2015, 10:28

Hi all, first post so sorry if I have already screwed up by posting here...

I wish to get into some high fidelity simulation of the sound created by the flow over a simple NACA airfoil using LES to model the sound sources in OpenFoam. I have managed to set up the case of solving RANS equations in OpenFoam using the simpleFoam solver. Up until now this has been relatively straightforward due to tutorials available online, but there is almost nothing on unsteady CFD modelling of an airfoil in OpenFoam, hence I am completely lost. Is there anyone out there that can walk me through how to set up a test case of using LES (or even DNS) of an airfoil? My Reynolds number of interest is relatively small (lets say 30,000 based on chord and I am mainly interested modelling the development of transition behaviour on the suction side and interaction with the trailing edge.

I intend to use the GMSH utility to create my Mesh about the airfoil.

Any advice would be greatly appreciated!

taxalian · May 12, 2015, 18:32

Are you interested in performing Hybrid RANS-LES type approach i.e. Detached Eddy Simulation.

In general, for LES you need a very high resolution hexahedral mesh and in order to capture the transition behavior over the suction side of the airfoil. In OpenFOAM there exists a transition model i.e. kklOmega turbulence model.

Make sure that this turbulence model works with the LES model, then you can perform the LES+transition modelling of an airfoil in OpenFOAM.

In OpenFOAM, there exists unsteady solvers like pimpleFoam in "tutorials/incompressible" folder, there you will find several tutorials.

Jack001 · May 13, 2015, 14:50

Thank you for your reply! I am interested in pure LES although I'm not sure - maybe the hybrid approach is possible as well.

So how would I start to experiment with this kklOmega turbulence model using pimpleFoam? I generally have no idea how to go about changing the turbulence model for a particular case, but I guess I could experiment. Particularly I'm not sure what I need to modify on the constant/ system directories of the problem I'm solving.

Another issue is that lets say I get everything to run. What is the best and quickest way to verify that my simulation is converging to a feasible solution? Should I look at mean quantities like pressure coefficient profile over the airfoil and compare to those of a RANS study I have done of the airfoil?

zeinelserfy · October 3, 2019, 00:57

Have you succeeded in running pure les simulation for flow around aerofoil as I am interested in that case?

zeinelserfy · April 12, 2020, 04:09

have anyone run les on openFOAM?

May 12, 2015, 10:28	Setting up LES of Airfoil in OpenFoam	#1
Jack001 Member Jack Join Date: May 2015 Posts: 98 Rep Power: 11	Hi all, first post so sorry if I have already screwed up by posting here... I wish to get into some high fidelity simulation of the sound created by the flow over a simple NACA airfoil using LES to model the sound sources in OpenFoam. I have managed to set up the case of solving RANS equations in OpenFoam using the simpleFoam solver. Up until now this has been relatively straightforward due to tutorials available online, but there is almost nothing on unsteady CFD modelling of an airfoil in OpenFoam, hence I am completely lost. Is there anyone out there that can walk me through how to set up a test case of using LES (or even DNS) of an airfoil? My Reynolds number of interest is relatively small (lets say 30,000 based on chord and I am mainly interested modelling the development of transition behaviour on the suction side and interaction with the trailing edge. I intend to use the GMSH utility to create my Mesh about the airfoil. Any advice would be greatly appreciated!

October 3, 2019, 00:57	have you succeeded in simulation it	#4
zeinelserfy New Member zein elserfy Join Date: May 2018 Posts: 25 Rep Power: 8	Have you succeeded in running pure les simulation for flow around aerofoil as I am interested in that case? TENE likes this.

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May 12, 2015, 18:32		#2
taxalian Senior Member Join Date: Nov 2010 Posts: 139 Rep Power: 16	Are you interested in performing Hybrid RANS-LES type approach i.e. Detached Eddy Simulation. In general, for LES you need a very high resolution hexahedral mesh and in order to capture the transition behavior over the suction side of the airfoil. In OpenFOAM there exists a transition model i.e. kklOmega turbulence model. Make sure that this turbulence model works with the LES model, then you can perform the LES+transition modelling of an airfoil in OpenFOAM. In OpenFOAM, there exists unsteady solvers like pimpleFoam in "tutorials/incompressible" folder, there you will find several tutorials.

May 13, 2015, 14:50		#3
Jack001 Member Jack Join Date: May 2015 Posts: 98 Rep Power: 11	Thank you for your reply! I am interested in pure LES although I'm not sure - maybe the hybrid approach is possible as well. So how would I start to experiment with this kklOmega turbulence model using pimpleFoam? I generally have no idea how to go about changing the turbulence model for a particular case, but I guess I could experiment. Particularly I'm not sure what I need to modify on the constant/ system directories of the problem I'm solving. Another issue is that lets say I get everything to run. What is the best and quickest way to verify that my simulation is converging to a feasible solution? Should I look at mean quantities like pressure coefficient profile over the airfoil and compare to those of a RANS study I have done of the airfoil?

April 12, 2020, 04:09		#5
zeinelserfy New Member zein elserfy Join Date: May 2018 Posts: 25 Rep Power: 8	have anyone run les on openFOAM?