inlet turbulence in LES (FLUENT)

dynamics · January 30, 2012, 18:05

Hi,
I am intending to use LES in FLUENT. I am using pressure based coupled solver with air as the working medium and assigning ideal gas properties. Since the flow is not incompressible, I cannot use velocity inlet boundary condition and hence the inlet turbulence generating techniques in FLUENT.
This page says (at the bottom) for all other boundary types apart from velocity inlet the flow is assumed as laminar in LES calculations. http://www.aeromech.usyd.edu.au/AMME...ug/node470.htm

Yes, I can increase the inlet length but I dont want to try it because of obvious reason (computation cost). Is there any alternative way to generate synthetic inlet turbulence (by hooking a UDF) with pressure inlet BC. If yes please explain or direct me to suitable references.

Thanks

Ebrahim · November 18, 2012, 06:15

Hi dynamics,
I have the same problem. I want to use vortex method perturbation for pressure inlet BC!
couldn't you find a solution for this problem?

Regards,
Ebrahim

sbaffini · November 18, 2012, 11:05

Quoting the Fluent 14 Manual:

"Both the vortex method and the spectral synthesizer are available for velocity inlet and pressure inlet boundary conditions".

Ebrahim · November 18, 2012, 15:55

Hi sbaffini

You are right. your comment helped me very much. Thank you

dynamics · April 6, 2014, 17:17

It was not available in Fluent 6.3 which I was using while posting the question.

January 30, 2012, 18:05	inlet turbulence in LES (FLUENT)	#1
dynamics New Member Join Date: Mar 2011 Posts: 7 Rep Power: 15	Hi, I am intending to use LES in FLUENT. I am using pressure based coupled solver with air as the working medium and assigning ideal gas properties. Since the flow is not incompressible, I cannot use velocity inlet boundary condition and hence the inlet turbulence generating techniques in FLUENT. This page says (at the bottom) for all other boundary types apart from velocity inlet the flow is assumed as laminar in LES calculations. http://www.aeromech.usyd.edu.au/AMME...ug/node470.htm Yes, I can increase the inlet length but I dont want to try it because of obvious reason (computation cost). Is there any alternative way to generate synthetic inlet turbulence (by hooking a UDF) with pressure inlet BC. If yes please explain or direct me to suitable references. Thanks Ebrahim likes this.

November 18, 2012, 11:05		#3
sbaffini Senior Member Paolo Lampitella Join Date: Mar 2009 Location: Italy Posts: 2,192 Blog Entries: 29 Rep Power: 39	Quoting the Fluent 14 Manual: "Both the vortex method and the spectral synthesizer are available for velocity inlet and pressure inlet boundary conditions". Ebrahim likes this.

April 6, 2014, 17:17		#5
dynamics New Member Join Date: Mar 2011 Posts: 7 Rep Power: 15	It was not available in Fluent 6.3 which I was using while posting the question. Ebrahim likes this.

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November 18, 2012, 06:15		#2
Ebrahim New Member Ebrahim Join Date: Mar 2010 Posts: 28 Rep Power: 16	Hi dynamics, I have the same problem. I want to use vortex method perturbation for pressure inlet BC! couldn't you find a solution for this problem? Regards, Ebrahim

November 18, 2012, 15:55		#4
Ebrahim New Member Ebrahim Join Date: Mar 2010 Posts: 28 Rep Power: 16	Hi sbaffini You are right. your comment helped me very much. Thank you