PotentialFOam

sampathevs · November 17, 2012, 13:47

Im continuously getting this error when Im running potentialFOam

continuity error = 9.077995892e-08
Interpolated U error = 1.798108527e-05

--> FOAM FATAL ERROR:
No valid model for viscous stress calculation.

From function forces::devRhoReff()
in file forces/forces.C at line 113.

FOAM exiting

its running, but in the last Im getting this . What does this mean? and wil this affect simpleFOAM?

masoudsh · June 20, 2016, 17:04

Hi

I have this error too,can anybody help me?
It's about adding forces code in controldict.

"--> FOAM FATAL ERROR:
No valid model for viscous stress calculation."

thanks
masoud

Kina · June 21, 2016, 05:30

That is actually not a problem. It is because potentialFoam cannot calculate the forces calculated in the controlDict functions. You can either ignore the message or simply run potentialFoam the following way.

Code:

potentialFoam -noFunctionObjects

Cheers
Alex

masoudsh · June 21, 2016, 08:16

Hello Alex

thanks by your answer.
I use "-noFunctionObjects" but this command overrides the function added in controldict,and I don't want to do that.
I want to calculate forces and forces coefficeint SO I added some commands in controldict.
Can you help me?

Best Regards
Masoud

matthewshorter · June 21, 2016, 09:41

Hello. PotentialFoam solves the inviscid incompressible equations and gives you what is effectively the analytical solution. According to the D'Alembert paradox, the drag on any object in the potential flow field will be 0. The lift may be non zero, but I don't think controlDict is the way to find that- look into using paraView or something other postprocessing tool for that.

masoudsh · June 21, 2016, 11:32

Hello Matthew

thanks for your reply
I use twophaseEulerfoam
and I have this error too.

"--> FOAM FATAL ERROR:
No valid model for viscous stress calculation."

November 17, 2012, 13:47	PotentialFOam	#1
sampathevs Member EMAVI V SURYA SAMPATH Join Date: Aug 2011 Location: Malaysia Posts: 85 Rep Power: 15	Im continuously getting this error when Im running potentialFOam continuity error = 9.077995892e-08 Interpolated U error = 1.798108527e-05 --> FOAM FATAL ERROR: No valid model for viscous stress calculation. From function forces::devRhoReff() in file forces/forces.C at line 113. FOAM exiting its running, but in the last Im getting this . What does this mean? and wil this affect simpleFOAM?

June 21, 2016, 05:30		#3
Kina Senior Member Alex Join Date: Jan 2014 Posts: 126 Rep Power: 12	That is actually not a problem. It is because potentialFoam cannot calculate the forces calculated in the controlDict functions. You can either ignore the message or simply run potentialFoam the following way. Code: potentialFoam -noFunctionObjects Cheers Alex

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June 20, 2016, 17:04		#2
masoudsh Member Join Date: Oct 2015 Posts: 48 Rep Power: 11	Hi I have this error too,can anybody help me? It's about adding forces code in controldict. "--> FOAM FATAL ERROR: No valid model for viscous stress calculation." thanks masoud

June 21, 2016, 08:16		#4
masoudsh Member Join Date: Oct 2015 Posts: 48 Rep Power: 11	Hello Alex thanks by your answer. I use "-noFunctionObjects" but this command overrides the function added in controldict,and I don't want to do that. I want to calculate forces and forces coefficeint SO I added some commands in controldict. Can you help me? Best Regards Masoud

June 21, 2016, 09:41		#5
matthewshorter New Member Matthew Shorter Join Date: Feb 2016 Posts: 10 Rep Power: 10	Hello. PotentialFoam solves the inviscid incompressible equations and gives you what is effectively the analytical solution. According to the D'Alembert paradox, the drag on any object in the potential flow field will be 0. The lift may be non zero, but I don't think controlDict is the way to find that- look into using paraView or something other postprocessing tool for that.

June 21, 2016, 11:32		#6
masoudsh Member Join Date: Oct 2015 Posts: 48 Rep Power: 11	Hello Matthew thanks for your reply I use twophaseEulerfoam and I have this error too. "--> FOAM FATAL ERROR: No valid model for viscous stress calculation."