Support for body-fitted meshes

[gzagaris]

Hello,

Does AMReX provide support for body-fitted, curvilinear meshes?

We could probably store the X, Y, Z coordinates as a field on each patch, but, I think we would need to override the field-interpolation function accordingly. Is that something that is supported in AMReX?

Thank you for all your help.

[WeiqunZhang]

I think the ERF code (https://github.com/erf-model/ERF) has some support for terrain with variable dz's. @AMLattanzi can probably chime in.

[AMLattanzi]

The ERF code noted by Weiqun does employ terrain-following height coordinates. This coordinate system allows for mesh deformation only in the z-direction; see Eqs. 2-4 and Eqs. 8a-8f of Sullivan (2014) for more details. In the ERF code, we store the physical z height and then compute all metric terms that enter the governing equations from that data structure --- i.e., J and \partial \xi_{i} / \partial x_{j} in Eq. 8 of Sullivan.

If you wanted to do something more general, I believe you could store the x, y, z positions as you noted and then compute the associated metric terms. For this case, you would just have a dense Jacobian matrix (ours is rather sparse due to the parametrization in Eq. 2 of Sullivan).