Inviscid flow Simulation in CFX

FAKHREDDINE · August 25, 2016, 00:01

Dear CFD community

I want to simulate the flow inside a Radial turbine but an Inviscid one,

How can I change the option in CFX to run an Inviscid flow simulation ?

Thank you for your help

ghorrocks · August 25, 2016, 07:11

CFX cannot run with zero viscosity. But you can define a fluid with such a low viscosity that it is in effect inviscid. Try reducing the viscosity of air (I assume it is air in your turbine) by a factor of 1000. If it diverges then try reducing by a factor of 100.

Opaque · August 25, 2016, 12:39

In addition to Glenn's suggestion, adding Free Slip Walls will also make it more consistent with an inviscid model

FAKHREDDINE · August 26, 2016, 05:48

Thank you for your answer

What about the Turbulence Model for an Inviscid flow ?

and the Turbulence option for an Inlet Boundary Condition ?

Kind Regards

ghorrocks · August 26, 2016, 06:54

Use a laminar flow model. There is no need to model the turbulence equations when they don't do anything.

August 25, 2016, 00:01	Inviscid flow Simulation in CFX	#1
FAKHREDDINE Member Yuva Join Date: Oct 2015 Location: Korea Rep of Posts: 33 Rep Power: 11	Dear CFD community I want to simulate the flow inside a Radial turbine but an Inviscid one, How can I change the option in CFX to run an Inviscid flow simulation ? Thank you for your help

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August 25, 2016, 07:11		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	CFX cannot run with zero viscosity. But you can define a fluid with such a low viscosity that it is in effect inviscid. Try reducing the viscosity of air (I assume it is air in your turbine) by a factor of 1000. If it diverges then try reducing by a factor of 100.

August 25, 2016, 12:39		#3
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	In addition to Glenn's suggestion, adding Free Slip Walls will also make it more consistent with an inviscid model

August 26, 2016, 05:48		#4
FAKHREDDINE Member Yuva Join Date: Oct 2015 Location: Korea Rep of Posts: 33 Rep Power: 11	Thank you for your answer What about the Turbulence Model for an Inviscid flow ? and the Turbulence option for an Inlet Boundary Condition ? Kind Regards

August 26, 2016, 06:54		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	Use a laminar flow model. There is no need to model the turbulence equations when they don't do anything.