[nandiganavishal]

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]

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

[Ben UWIHANGANYE]

Originally Posted by nandiganavishal

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

Hello,

Have you been able to solve that problem?
May you help also to know how I can solve the same

Regard!

[chchung]

for U, it should be

value uniform (0 -0.1 0); // water is injected at 0.1m/s

as the water is dropped down in the y-direction.


for the p, I got error for buoyantPressue, so I changed it to fixedFluxPressure.