Thank you for your fast response and your help.

I was able to transform the equations. However, I'm just wondering if it is possible to calculate the divergence of a matrix directly. If I want to transform the Reynolds Stress tensor as well, I would need to calculte the divergence of this tensor because I don't think there is a possiblity to rewirte the tensor in a different way.

Is there an elegant way to do this, or do i have to do it each component at a time?

Thanks again for your help.