4.7. Non-Boussinesq Solver

CROCO can be used in a Boussinesq hystrostatic mode, or a non-hydrostatic, non-boussinesq mode (NBQ). The Non-Hydrostatic approach is based on the relaxation of the Boussinesq approximation instead of solving a Poisson system. It replaces the barotropic mode solver by a fully 3D fast mode solver, resolving all waves down to acoustic waves. The barotropic mode is part of the fast mode in this case. Depending on the physical problem, the sound speed can be decreased to the maximum wave velocity one wants to solve. The NH solver can be used in problems from a few tens of meters to LES or DNS resolutions. It comes with monotonicity preserving advection schemes (WENO5, TVD) and fully 3D turbulent closure schemes.

Related CPP options (for users):

NBQ	Activates Non-hysrostatic, non-Boussinesq solver