How to switch off wall functions in ANSYS FLUENT?

harshavardhanps3839 · December 11, 2020, 05:07

I am doing my simulations in ANSYS Fluent. I am trying to resolve viscous sub layer (in a closed duct with air flowing at a Mach number<0.1, flow occurs at room temperature). I prepared my mesh with y+ value~1 and i am using SST K-OMEGA turbulence model.please help me with the following questions.

1) There is no option to turn off wall function in Ansys Fluent how to switch off wall functions because i am trying to resolve viscous sub layer accurately with out wall function. My objective is to predict exact location of flow separation.

2)OR will wall functions be automatically turned off if my mesh is fine enough to produce a y+~1?

3)Do i need to solve energy equation as viscosity dissipation turns high grade mechanical energy into heat? How much error can I expect in the solutions if the energy equation is turned off?

your help is much appreciated.

duri · December 11, 2020, 07:50

If you don't turn on any wall function it will use wall integration approach. Enhanced wall function will take care automatically based on yplus. No need to turn on energy equation.

December 11, 2020, 05:07	How to switch off wall functions in ANSYS FLUENT?	#1
harshavardhanps3839 New Member harshavardhanps Join Date: Dec 2020 Posts: 13 Rep Power: 5	I am doing my simulations in ANSYS Fluent. I am trying to resolve viscous sub layer (in a closed duct with air flowing at a Mach number<0.1, flow occurs at room temperature). I prepared my mesh with y+ value~1 and i am using SST K-OMEGA turbulence model.please help me with the following questions. 1) There is no option to turn off wall function in Ansys Fluent how to switch off wall functions because i am trying to resolve viscous sub layer accurately with out wall function. My objective is to predict exact location of flow separation. 2)OR will wall functions be automatically turned off if my mesh is fine enough to produce a y+~1? 3)Do i need to solve energy equation as viscosity dissipation turns high grade mechanical energy into heat? How much error can I expect in the solutions if the energy equation is turned off? your help is much appreciated.

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December 11, 2020, 07:50		#2
duri Senior Member duri Join Date: May 2010 Posts: 245 Rep Power: 16	If you don't turn on any wall function it will use wall integration approach. Enhanced wall function will take care automatically based on yplus. No need to turn on energy equation.