[wcpvandervelden]

Dear all,

I am trying to build a solver which solves a non-homogeneous wave equation.

You may ask, why such a solver? It is used for solving a simplified version of the Ffowcs Williams Hawkings differential equation, used in aeroacoustics. To be specific, I would like to use Curle's analogy, and only consider the pressure perturbation at the wall. Therefore I wrote some code which extracts the pressure at the boundary, I multiply it with the normal outward vector, and taking the divergence of the volVectorField (which is zero in the internal field, and has values in the boundary field) to create a volScalarField. Next, I forced this last volScalarField to be zero in the internal field (initial there were some values because of the corners of the geometry)

Now the next step is to solve the wave equation throughout the domain, with the source term as indicated above.

I started by simply using the following relation:

solve((fvm::d2dt2(rhoPrimeCurle) - c0 * c0 * fvm::laplacian(rhoPrimeCurle)== -CurleTerm));

However, due to the fact that the source term only consist of values at the wall, no solution can be obtained. There are 0 iterations required to solve this.

I am thinking this is because of the fact that the internalField = 0. Therefore, I would like to fill the CurleTerm.internalField() somehow by interpolating the values from the boundary to the nearest cells.

Is there anyone who has some experience with this method, or perhaps, is there anyone with a brilliant idea how to omit this. I assume someone tried to implement the FW-H equation before in OF.

Many thanks in advance