forces in interFoam

Svensson · October 21, 2011, 08:55

Hello all!

I have some problems to get forces with standard library libforces.so for interFoam solver. I found one article from workshop, in which author made own library (libhullForce.so)(http://www.openfoamworkshop.org/6th_...m/training.htm) to calculate forces in two-phase liquid. I took his case with BC, controlDict, fvSchemes and fvSolution and changed only geometry. But result that i got is not correct. Forces are greater that in experimet about 5-8 times. I saw my controlDict and found that in below entry

forces
{

type forces;

functionObjectLibs ("libforces.so");

patches (hull_wall);

rhoName rhoInf;

rhoInf 1000;

CofR (0 0 0);

outputControl timeStep;

outputInterval 1;

}

there is only one density - rhoInf equals to 1000. Can libforces.so calculate forces only for monophase liquids? I use openFoam 2.0.0. Is my guess true? How is it possible to get forces components manually?

bojiezhang · April 14, 2012, 08:02

Hello Svensson:

I face the same problem as you. Have you found a satisfied way to calculate the force in the two-phase flow? Could you give me some advice?

Thank you!

bojiezhang

daveatstyacht · May 9, 2012, 14:31

Svensson,
Currently you are setting the rho equal to rhoInf for all force calcs. Use "rhoName rho;" since this is the scalar field that varies in space with alpha.

Hope this helps,
Dave

October 21, 2011, 08:55	forces in interFoam	#1
Svensson New Member Alexander Join Date: Dec 2009 Location: Saint-Petersburg Posts: 29 Rep Power: 16	Hello all! I have some problems to get forces with standard library libforces.so for interFoam solver. I found one article from workshop, in which author made own library (libhullForce.so)(http://www.openfoamworkshop.org/6th_...m/training.htm) to calculate forces in two-phase liquid. I took his case with BC, controlDict, fvSchemes and fvSolution and changed only geometry. But result that i got is not correct. Forces are greater that in experimet about 5-8 times. I saw my controlDict and found that in below entry forces { type forces; functionObjectLibs ("libforces.so"); patches (hull_wall); rhoName rhoInf; rhoInf 1000; CofR (0 0 0); outputControl timeStep; outputInterval 1; } there is only one density - rhoInf equals to 1000. Can libforces.so calculate forces only for monophase liquids? I use openFoam 2.0.0. Is my guess true? How is it possible to get forces components manually?

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April 14, 2012, 08:02		#2
bojiezhang Member bojiezhang Join Date: Jan 2010 Posts: 64 Rep Power: 16	Hello Svensson: I face the same problem as you. Have you found a satisfied way to calculate the force in the two-phase flow? Could you give me some advice? Thank you! bojiezhang

May 9, 2012, 14:31		#3
daveatstyacht Senior Member Dave Join Date: Jul 2010 Posts: 100 Rep Power: 16	Svensson, Currently you are setting the rho equal to rhoInf for all force calcs. Use "rhoName rho;" since this is the scalar field that varies in space with alpha. Hope this helps, Dave