Implementation of DGSEM solver settings through DGMulti

[teddyz1999]

Since I want to solve the three-dimensional Navier-Stokes equations using DGSEM, but DGSEM solver only supports generating grids with 2^N points in each direction, while I want to specify a particular number of grids in each direction, DGMultiMesh seems to be able to achieve this functionality. Therefore, I want to implement DGSEM through the DGMulti solver. How should I set up a DGMulti solver?

dg = DGMulti(polydeg = 3, element_type = Hex(), approximation_type = GaussSBP(),
             surface_integral = SurfaceIntegralWeakForm(flux_lax_friedrichs),
             volume_integral = VolumeIntegralFluxDifferencing(flux_ranocha))

[DanielDoehring]

DGSEM solver only supports generating grids with 2^N points in each direction

that is only true for the TreeMesh and is independent of the solver used. The P4estMesh offers maximum flexibility, see e.g.

https://github.com/trixi-framework/Trixi.jl/blob/main/examples/p4est_2d_dgsem/elixir_navierstokes_NACA0012airfoil_mach08.jl

or

Trixi.jl/examples/p4est_2d_dgsem/elixir_navierstokes_viscous_shock.jl

Lines 103 to 107 in f09a707

	trees_per_dimension = (8, 2)
	mesh = P4estMesh(trees_per_dimension,
	polydeg = 3, initial_refinement_level = 0,
	coordinates_min = coordinates_min, coordinates_max = coordinates_max,
	periodicity = (false, true))

for an example that employs a 8x2 mesh.
Both employ a DGSEM solver.