[Pavithra]

Hello Everyone,

I am developing a solver for Electrohydrodynamics by modifying the PimpleFoam. I need to add a body force term to the momentum equation. I have calculated the body force (F) in a file called mySource.H.

The body force is the Coulomb force calculated by solving the potential equation and charge density equation.

I tried adding the body force to the momentum equation in UEqn.H as follows:

    
fvVectorMatrix UEqn
    (
        fvm::ddt(U) + fvm::div(phi, U)
      + MRF.DDt(U)
      + turbulence->divDevReff(U)
     ==
        fvOptions(U)
    + F
    );

I tried to validate the solver. The solver produces very accurate results that match with the literature when symmetry and periodic boundary conditions are applied on the lateral walls of the cavity. But when rigid walls are used the solver produces very strange results.

Any hints on the strange behavior while using rigid walls will be very helpful.

Also, I read in a thread that adding the source term to UEqn directly leads to poor numerical stability. Thus, I am trying to add the source using fvOptions. Could someone please give me a direction on how to use the vectorCodedSource fvOptions to add the body force.

My body force F is volVectorField.

Thank You.

[YHP]

Hello, has your problem been solved? I added electrical strength to UEqn, and encountered a situation similar to yours when solving. If your problem is solved, can you tell me the solution?

[pferro]

Originally Posted by Pavithra

Hello Everyone,

I am developing a solver for Electrohydrodynamics by modifying the PimpleFoam. I need to add a body force term to the momentum equation. I have calculated the body force (F) in a file called mySource.H.

The body force is the Coulomb force calculated by solving the potential equation and charge density equation.

I tried adding the body force to the momentum equation in UEqn.H as follows:

    
fvVectorMatrix UEqn
    (
        fvm::ddt(U) + fvm::div(phi, U)
      + MRF.DDt(U)
      + turbulence->divDevReff(U)
     ==
        fvOptions(U)
    + F
    );

I tried to validate the solver. The solver produces very accurate results that match with the literature when symmetry and periodic boundary conditions are applied on the lateral walls of the cavity. But when rigid walls are used the solver produces very strange results.

Any hints on the strange behavior while using rigid walls will be very helpful.

Also, I read in a thread that adding the source term to UEqn directly leads to poor numerical stability. Thus, I am trying to add the source using fvOptions. Could someone please give me a direction on how to use the vectorCodedSource fvOptions to add the body force.

My body force F is volVectorField.

Thank You.

Hello,

Using fvOptions will also add the force in the source term of fvVectorMatrix UEqn.

Good luck