pimpleFoam synthetic turbulence

tom.opt · March 10, 2020, 09:13

Hi All,

I'm interested in setting up an LES simulation with pimpleFoam for a spray nozzle.I want to introduce synthetic turbulence at the inlet.

I saw that this has been done before with channel395 tutorial

https://develop.openfoam.com/Develop...hannel395DFSEM

https://www.openfoam.com/documentati...ity-dfsem.html

The tutorial uses : Inlet patch Reynolds stress, velocity and turbulence length scale which have been extracted from DNS.

I do not have access to DNS or experimental data.
Would it still be possible for me to run the DFSEM?

Additionally, in my converged simpleFoam solution for my BC i set up the inlet as totalPressure inlet and the outlet as fixedValue. Would it still be possible to use these conditions with the DFSEM?

Tom

H.Tofighian · March 16, 2020, 19:24

I think you can estimate the value of Reynolds stress, velocity, and turbulence length scale at the inlet, but you need to consider a bit of inlet pipe. During the simulation, the inlet flow fields are resolved and modified in the pipe.

You can also use of mapped boundary condition, but in this case, You need a longer inlet pipe. It may also take a long time for the flow to be turbulence.

March 10, 2020, 09:13	pimpleFoam synthetic turbulence	#1
tom.opt Member Tom Join Date: Apr 2017 Posts: 50 Rep Power: 9	Hi All, I'm interested in setting up an LES simulation with pimpleFoam for a spray nozzle.I want to introduce synthetic turbulence at the inlet. I saw that this has been done before with channel395 tutorial https://develop.openfoam.com/Develop...hannel395DFSEM https://www.openfoam.com/documentati...ity-dfsem.html The tutorial uses : Inlet patch Reynolds stress, velocity and turbulence length scale which have been extracted from DNS. I do not have access to DNS or experimental data. Would it still be possible for me to run the DFSEM? Additionally, in my converged simpleFoam solution for my BC i set up the inlet as totalPressure inlet and the outlet as fixedValue. Would it still be possible to use these conditions with the DFSEM? Tom

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March 16, 2020, 19:24		#2
H.Tofighian New Member Hesam Tofighian Join Date: Mar 2019 Posts: 11 Rep Power: 7	I think you can estimate the value of Reynolds stress, velocity, and turbulence length scale at the inlet, but you need to consider a bit of inlet pipe. During the simulation, the inlet flow fields are resolved and modified in the pipe. You can also use of mapped boundary condition, but in this case, You need a longer inlet pipe. It may also take a long time for the flow to be turbulence.