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-   -   Continuity error cannot be removed by adjusting the outflow (http://www.cfd-online.com/Forums/openfoam-solving/102950-continuity-error-cannot-removed-adjusting-outflow.html)

fontania June 7, 2012 01:12

Continuity error cannot be removed by adjusting the outflow
 
OpenFOAMers,

I have a case that receives this continuity error. I am running the application buoyantBoussinesqPimpleFoam. Turbulence is "on" and I am using the RNGkEpsilon RASModel. I don't think my case is overdefined, but I have added below my 0/p, 0/U, and 0/p_rgh files Any help would be appreciated.

Thank you in advance

[0]
[0] --> FOAM FATAL ERROR:
[0] Continuity error cannot be removed by adjusting the outflow.
Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow.
Total flux : 136228.04
Specified mass inflow : 296.39639
Specified mass outflow : 0
Adjustable mass outflow : 2.10095737e-12

FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
wall_1
{
type zeroGradient;
}
inlet
{
type zeroGradient;
}
wall-ceiling
{
type zeroGradient;
}
wall-floor
{
type zeroGradient;
}
wall-side-1-1
{
type zeroGradient;
}
wall-side-1-2
{
type zeroGradient;
}
wall-side-2-2
{
type zeroGradient;
}
wall-side-2-1
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
wall-tube
{
type zeroGradient;
}

}

FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p_rgh;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{

wall_1
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
inlet
{
type zeroGradient;
}
wall-ceiling
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
wall-floor
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
wall-side-1-1
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
wall-side-1-2
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
wall-side-2-2
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
wall-side-2-1
{
type buoyantPressure;
rho rhok;
value uniform 0;
}
outlet
{
type zeroGradient;
}
wall-tube
{
type buoyantPressure;
rho rhok;
value uniform 0;
}

}

FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{

wall_1
{
type fixedValue;
value uniform (0 0 0);
}
inlet
{
type fixedValue;
value uniform (0 0 7.67482);
}
wall-ceiling
{
type fixedValue;
value uniform (0 0 0);
}
wall-floor
{
type fixedValue;
value uniform (0 0 0);
}
wall-side-1-1
{
type fixedValue;
value uniform (0 0 0);
}
wall-side-1-2
{
type fixedValue;
value uniform (0 0 0);
}
wall-side-2-2
{
type fixedValue;
value uniform (0 0 0);
}
wall-side-2-1
{
type fixedValue;
value uniform (0 0 0);
}
outlet
{
type zeroGradient;
}
wall-tube
{
type fixedValue;
value uniform (0 0 0);
}

}

curiosity October 9, 2012 10:36

Hi Fontania,

Im not very sure about this but its a problem that Ive had and Ive solved it adjusting velocities. This is: v_inlet*A_inlet=v_outlet*A_outlet

If you know three of these parameters (areas and initial velocity) you can obtain the other one and put it on the inicial conditions to make the continuity ecuation works... but, I repeat, Im not so sure about this, sorry

Regards


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