# InterFoam viscosity problem / possible bug

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 July 15, 2012, 01:57 #21 Senior Member   Ehsan Join Date: Mar 2009 Posts: 112 Rep Power: 16 Dear All Please see Eq. 4 in the paper below: http://www.marinepropulsors.com/proc...0Propulsor.pdf May I ask you whether in OpenFOAM the same equation including turbulence effects are used for viscosity of two phase flow or only simple averaging from laminar values are employed? Best Regards ScarFace likes this.

 August 16, 2012, 17:47 #22 New Member   David Join Date: May 2012 Location: Canada Posts: 12 Rep Power: 13 any news about this issue , I am using a Herschel Bulkely model and tried setting the momentum predictor On or Off and I usually get unstability in case of turniing the momentum predictor on and less gravitional effect when turninhg it off ?? this problem is becoming annoying and i had no clue about it now!!1

October 29, 2012, 03:43
#23
Senior Member

Mohsen KiaMansouri
Join Date: Jan 2010
Location: CFD Lab
Posts: 118
Rep Power: 15
Quote:
 Originally Posted by ehsan Dear All Please see Eq. 4 in the paper below: http://www.marinepropulsors.com/proc...0Propulsor.pdf May I ask you whether in OpenFOAM the same equation including turbulence effects are used for viscosity of two phase flow or only simple averaging from laminar values are employed? Best Regards
Dear Ehsan,

please take a look at the interFoam solver. you will see sth like this:

surfaceScalarField muEff
(
"muEff",
twoPhaseProperties.muf()
+ fvc::interpolate(rho*turbulence->nut())
);

So OF will Consider both viscosities

Best Regards,
Mohsen

January 31, 2020, 02:42
#24
Senior Member

krishna kant
Join Date: Feb 2016
Posts: 132
Rep Power: 9
Hello All

I am performing a test case of static bubble where the bubble column is kept at zero gravity. The test case is from M.Hermann paper http://multiphase.asu.edu/paper/jcp_2007.pdf of density and viscosity ratio 1. Here we plot La vs Ca to evaluate the spurious current generated. He has chosen viscosity=0.1, surface tension coefficient=1 and varied the density to vary the La number and obtain Ca of the order of 1e-6.

But for interFoam I am getting Ca of the order of 1e-4 for viscosity=0.1 and Ca of the order of 1e-6 for viscosity=1 keeping value of La same. Is it possible to get a solution independent of viscosity value for this problem? How can I optimize the solution parameters?

The current solution parameters that I am using is attached here.
Attached Files
 staticbubb.zip (59.5 KB, 2 views)

 March 30, 2020, 04:25 #25 Senior Member   Albrecht vBoetticher Join Date: Aug 2010 Location: Zürich, Swizerland Posts: 234 Rep Power: 15 Hello Your Mesh is qite coarse, as the volume-of-fluid method is quite sensitive to grid resolution. you have the same high density for water and air and your solution is affected by sigma in your transportProperties dict and your simulation neglects turbulence. I suggest you look at interFOAM tutorial cases.

 Tags interfoam, viscosity