Discussion Forum

Hello Everyone,

I am trying to conduct a 2-D scattering simulation of an acoustic cloak where the material properties, density and bulk modulus, are given at discrete material points, and inhomogeneous and anisotropic (for the density only).

To be more specific below are the details on the bulk and the density (my struggles and my question pertain to the implementation of the anisotropic and inhomogeneous density):

1. The bulk modulus is scalar and only given at N discrete points of coordinates (x,y). So I have a NX3 matrix for the bulk where the first two columns represents pairs of (x,y) coordinates at the discrete material points, and the last column represents the corresponding bulk modulus at the discrete material points.

Here, I understand that I can have Comsol do a 2-D interpolation function using the above mentioned table of the bulk modulus. So not a big issue....

2. Unlike the bulk modulus, the density is anisotropic in addition to its discrete and inhomogeneous nature. So instead of a NX3 matrix, I rather have a NX3 cell array where the first two columns represents pairs of (x,y) coordinates at the discrete material points as in the case of the bulk. However, the last column is no longer composed of scalars, but rather N matrices (2X2) corresponding to the anisotropic density at the discrete material points.

My questions are the following:

- Does Comsol allow anisotropic material properties?

- If yes, in this specific case, how can one get discrete anisotropic material properties into Comsol since it requires some kind of tensor interpolation?

I am thinking to just do a component-wise interpolation of the individual tensor as a start if there is a way to do that in Comsol. By that I mean to create four NX3 arrays where the third columns are just the individual scalar components of the density tensor corresponding to each discrete material points. Then, do a 2-D interpolation of these component.

- Would Comsol allows tensor entries (which are scalars) to be interpolated based on a provided table of values? I could not find it ...

- Is there another module, which may allow this be done easily? I suspect anisotropic materials are not stranger to EM and test data are usually discrete....

Note that I am running Comsol 4.4.

Any help or suggestion will be greatly appreciated.

Thanks,

Saliou