[Nicolao]

Hey everyone,

I'm trying to create a solver for electrohydrodynamics in OpenFoam. I've found one solver at this link

http://openfoamwiki.net/index.php/Co...ectromagnetics

but I'm having some problems about it.

The charge density in the case (EHDdroplet) is not calculated. And I don't understand why the electric force has been set up at the surface (I guess that it is at the surface) at the right side of the N-S equation.

I'm wondering if there is anyone working on a solver for EHD cases that could help me with it.

Just in case, I'm working with atomization process.

Thanks for any help!!

[salehda]

Hi Nicola ,

any updates about these ?? I am trying to use it too , but I am stuck with compiling it

Thanks
David

[Ivooo]

Hi,

I am currently working on an extended version of the EHDFoam model, using the version posted on the wiki as a base, but also using the JCP article of Lopez Herrera et al. [1] as a guide. This paper outlines how a charge density is generated on the interface between two fluids due to an electric field. As such, I am now able to simulate both dielectric and conducting fluids (any combination of the two), and I was able to verify most cases outlined in the paper. I'll put it on the wiki as soon as we have everything worked out in detail, but I am willing to collaborate with the last steps of development. Let me know if you're interested.

[1] Journal of Computational Physics 230:1939-1955, 2011

[Ivooo]

Originally Posted by Nicolao

Hey everyone,

I'm trying to create a solver for electrohydrodynamics in OpenFoam. I've found one solver at this link

http://openfoamwiki.net/index.php/Co...ectromagnetics

but I'm having some problems about it.

The charge density in the case (EHDdroplet) is not calculated. And I don't understand why the electric force has been set up at the surface (I guess that it is at the surface) at the right side of the N-S equation.

I'm wondering if there is anyone working on a solver for EHD cases that could help me with it.

Just in case, I'm working with atomization process.

Thanks for any help!!

Just to answer your question, the charge density in the original EHDFoam model is not calculated, it is only transported so you'll have to initialise the charge densities e.g. using setFields. The electric force is solved explicitly (RHS), but I dont see a problem in that; it is the normal way of incorporating an additional force in the NS eqs.

[Ivooo]

Originally Posted by salehda

Hi Nicola ,

any updates about these ?? I am trying to use it too , but I am stuck with compiling it

Thanks
David

I'm not sure what goes wrong in your case, but the EHDFoam has been written using OF1.5. I can't tell what happens if you compile it with a more recent version of OF, I started off by updating EHDFoam (both the library and the executable) to match the 2.1 version of OF.

[Nicolao]

Originally Posted by Ivooo

Hi,

I am currently working on an extended version of the EHDFoam model, using the version posted on the wiki as a base, but also using the JCP article of Lopez Herrera et al. [1] as a guide. This paper outlines how a charge density is generated on the interface between two fluids due to an electric field. As such, I am now able to simulate both dielectric and conducting fluids (any combination of the two), and I was able to verify most cases outlined in the paper. I'll put it on the wiki as soon as we have everything worked out in detail, but I am willing to collaborate with the last steps of development. Let me know if you're interested.

[1] Journal of Computational Physics 230:1939-1955, 2011

Hey Ivooo, I also used the paper from Herrera as a base. And my solver is actually working quite fine. The fact is that I didn't implemented the equations from 13 to 18 (from the paper) on the solver. I want to know if it is necessary to put them on the solver, or if they are inherent to the solution of the Maxwell's equations.
(I don't know if that was clear enough...)

If you could help me on implementing them (equations 13 to 18) it would be of great help.

About the charge density, I initialized it on the 0 folder, and set as 0 as initial condition. And it worked. It appears only at the interface and the electric force too.

Thanks!

[Rob Bacon]

Hi, I'm looking to use a working EHD solver for analysis of Taylor cone ejection and I was wondering if either of your solvers is at a working stage yet? If so I'd be very interested in 'beta testing' it for you!

[Ivooo]

Originally Posted by Rob Bacon

Hi, I'm looking to use a working EHD solver for analysis of Taylor cone ejection and I was wondering if either of your solvers is at a working stage yet? If so I'd be very interested in 'beta testing' it for you!

Sorry for the late response. I'll publish the code as soon as I have permission from my supervisors/sponsors (I will get that permission, shouldnt worry about it). Our intention is to publish it including several validation and example cases so people can start using it right away.

[Rob Bacon]

Hi Ivooo, that would be great, looking forward to trying it!

[Mojtaba.a]

Originally Posted by Ivooo

Sorry for the late response. I'll publish the code as soon as I have permission from my supervisors/sponsors (I will get that permission, shouldnt worry about it). Our intention is to publish it including several validation and example cases so people can start using it right away.

Dear Ivo,
have you got permission from you supervisor to publish the code?
I really look forward to it.

Thank you

[Ivooo]

Originally Posted by Mojtaba.a

Dear Ivo,
have you got permission from you supervisor to publish the code?
I really look forward to it.

Thank you

Hi,

We are preparing an article about it now, which also involves a multi-region solver for EHD. If we're confident that the paper gets accepted I can publish it.


Cheers

[chirs]

Hi David,

Currently, I am trying to set up EHD solver in openFOAM 2.2.2. but I can't get compile it, please could you give some advise; how to do it? how did you do it ?

Thanks in advance,
Christian

[salehda]

Hi Chris,

I did not compile it , I left openFOAM and then I am getting back to it. I tried compiling a new library o include the two phase mixture, every thing goes well until it gives me an error

In file included from EHDTwoPhaseMixture/EHDtwoPhaseMixture.C:27:0:
EHDTwoPhaseMixture/EHDtwoPhaseMixture.H:190:39: error: conflicting return type specified for ‘virtual const volScalarField& Foam::EHDtwoPhaseMixture::nu() const’
../EHDincompressible/transportModel/transportModel.H:84:37: error: overriding ‘virtual Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam::transportModel::nu() const’
make: *** [Make/linux64GccDPOpt/EHDtwoPhaseMixture.o] Error 1

Any idea, how to solve this ??

[chirs]

Hi David,
Sorry for my late answer, I fix that problem as follows:
changing the 190 line for:
//- Return the kinematic laminar viscosity
virtual tmp<volScalarField& nu() const
{
return nu_;
}

[salehda]

Thanks Chris,

I fixed this but now I am getting this ,
gammaEqnSubCycle.H: In function ‘int main(int, char**)’:
gammaEqnSubCycle.H:3:15: error: ‘piso’ was not declared in this scope
In file included from gammaEqnSubCycle.H:22:0,
from EHDFoam.C:75:
gammaEqn.H:6:26: error: ‘class Foam::interfaceProperties’ has no member named ‘cGamma’
In file included from gammaEqnSubCycle.H:30:0,
from EHDFoam.C:75:
gammaEqn.H:6:26: error: ‘class Foam::interfaceProperties’ has no member named ‘cGamma’
/opt/openfoam222/src/finiteVolume/lnInclude/readPISOControls.H:3:15: warning: unused variable ‘nOuterCorr’ [-Wunused-variable]
/opt/openfoam222/src/finiteVolume/lnInclude/readPISOControls.H:15:16: warning: unused variable ‘transonic’ [-Wunused-variable]
/opt/openfoam222/src/finiteVolume/lnInclude/readPISOControls.H:3:15: warning: unused variable ‘nOuterCorr’ [-Wunused-variable]
/opt/openfoam222/src/finiteVolume/lnInclude/readPISOControls.H:6:15: warning: unused variable ‘nCorr’ [-Wunused-variable]
/opt/openfoam222/src/finiteVolume/lnInclude/readPISOControls.H:12:16: warning: unused variable ‘momentumPredictor’ [-Wunused-variable]
/opt/openfoam222/src/finiteVolume/lnInclude/readPISOControls.H:15:16: warning: unused variable ‘transonic’ [-Wunused-variable]
/opt/openfoam222/src/finiteVolume/lnInclude/readTimeControls.H:38:8: warning: unused variable ‘maxDeltaT’ [-Wunused-variable]
make: *** [Make/linux64GccDPOpt/EHDFoam.o] Error 1

It seems that all the variable names has changed from the different versions , Can you please help me with that or can you upload the updated code if you were able to compile it.

Thank you

[salehda]

Originally Posted by Ivooo

Hi,

We are preparing an article about it now, which also involves a multi-region solver for EHD. If we're confident that the paper gets accepted I can publish it.


Cheers

Hi Ivoo,

Any updates on that ?

[Ivooo]

Originally Posted by salehda

Hi Ivoo,

Any updates on that ?

Yes, the paper has been submitted and is currently under review. It has been about a month now, so I guess I will hear something soon.

[chirs]

hi Ivo,
I was reading your conference paper "An OpenFOAM-based electro-hydrodynamical model", it is interesting, I am working in something similar, but I could not set up the validation case for charge relaxation, please could you give me an idea how to set up it?

Best regards,

Chris

[Ivooo]

Originally Posted by chirs

hi Ivo,
I was reading your conference paper "An OpenFOAM-based electro-hydrodynamical model", it is interesting, I am working in something similar, but I could not set up the validation case for charge relaxation, please could you give me an idea how to set up it?

Best regards,

Chris

If I recall correctly, I have used the funkySetFields in order to init a Gaussian charge bump. Perhaps that's where you are stuck?

Anyway, perhaps it is coincidence but today I received notification that our article on interFoamEHD including multi-region is available online. That means I can also upload the code and validation cases I have used.

I am currently digging through the files (I want the package with solvers, utilities, scripts and cases to be clean and tested once more). I will get back to this soon.

[chirs]

Originally Posted by Ivooo

If I recall correctly, I have used the funkySetFields in order to init a Gaussian charge bump. Perhaps that's where you are stuck?

Anyway, perhaps it is coincidence but today I received notification that our article on interFoamEHD including multi-region is available online. That means I can also upload the code and validation cases I have used.

I am currently digging through the files (I want the package with solvers, utilities, scripts and cases to be clean and tested once more). I will get back to this soon.

Ivo, thanks to answer. Yes, the Gaussian charge bump is the problem. I will try your suggestion.
Congratulations for your paper, it will be great if you can upload the code and the validations.

Best Regards,

Christian Narvaez