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-   -   inkjet model using interFoam (http://www.cfd-online.com/Forums/openfoam/106884-inkjet-model-using-interfoam.html)

nandiganavishal September 11, 2012 13:22

inkjet model using interFoam
 
Dear Foamers,

I am trying to simulate the inkjet problem from a nozzle. I am using the interFoam solver to model the same. The geometry is similar to the one discussed in this tutorial http://www.tfd.chalmers.se/~hani/kur...Hemida_VOF.pdf

However, I was not able to get the correct results as discussed in the tutorial. I would like to know what boundary conditions have to be specified for pressure and the velocity.

I have considered the following for U

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (-0.1 0 0); // water is injected at 0.1m/s
}
inletWall
{
type fixedValue;
value uniform (0 0 0);
}
bottleWall
{
type fixedValue;
value uniform (0 0 0);
}
atmosphere
{
type pressureInletOutletVelocity;
value uniform (0 0 0);
}
frontAndBack
{
type empty;
}
}

and for pressure

boundaryField
{
inlet
{
type buoyantPressure;
value uniform 0;
}

inletWall
{
type zeroGradient;
}

bottleWall
{
type zeroGradient;
}

atmosphere
{
type totalPressure;
p0 uniform 0;
U U;
phi phi;
rho rho;
psi none;
gamma 1;
value uniform 0;
}

frontAndBack
{
type empty;
}
}

while for alpha1

boundaryField
{
inlet
{
type fixedValue;
value uniform 1;
}
inletWall
{
type zeroGradient;
}
bottleWall
{
type zeroGradient;
}
atmosphere
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}
frontAndBack
{
type empty;
}


I would like to know if they are consistent.

Kindly let me know !!

Thanks

Regards

Vishal

sahas October 11, 2012 02:40

I think there is the same problem with simulation of inkjet breakup due to external oscillations.

The formulation of a problem is very simple (see http://www.foamcfd.org/Nabla/main/mainhe22.html#inkJet for example): there is a water axisymmetric jet (about 100mkm diameter) with oscillating speed U0+dU*sin(Wt), U0 is about 25 m/s, dU is about 1-10%U0, W is about 1-100kHz.
It should breaks up to droplets but for interFoam 2.0 and 2.1 it does not. With OpenFoam 1.5 all is fine and is in excellent agreement with the experiment.
Sometimes later I hope to post problem formulation for OpenFOAM.

I think there is a serious bug in interFoam.

P.S. This is our article about results obtained with interFoam 1.5
http://www.sciencedirect.com/science...77050910000785


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