Towards a geometric variational discretization of compressible fluids: the rotating shallow water equations
For computational fluid dynamics researchers, this provides a structure-preserving discretization for compressible flows, though it is an incremental extension of prior work on incompressible fluids.
This work extends geometric variational discretization from incompressible to compressible fluids, applying it to rotating shallow water equations on irregular 2D meshes. The scheme conserves mass and total energy, accurately represents nonlinear dynamics, and approximates frequency relations well.
This paper presents a geometric variational discretization of compressible fluid dynamics. The numerical scheme is obtained by discretizing, in a structure preserving way, the Lie group formulation of fluid dynamics on diffeomorphism groups and the associated variational principles. Our framework applies to irregular mesh discretizations in 2D and 3D. It systematically extends work previously made for incompressible fluids to the compressible case. We consider in detail the numerical scheme on 2D irregular simplicial meshes and evaluate the scheme numerically for the rotating shallow water equations. In particular, we investigate whether the scheme conserves stationary solutions, represents well the nonlinear dynamics, and approximates well the frequency relations of the continuous equations, while preserving conservation laws such as mass and total energy.