  This work deals with Direct Numerical Simulations (DNS) and Large Eddy
Simulations (LES) of turbulent gravity currents, performed by means of a
Discontinuous Galerkin (DG) Finite Element method. In particular, a DG-LES
approach in which the filter operation is built in the numerical discretization
has been employed, similarly to VMS approaches. Numerical simulations of
non-Boussinesq lock-exchange benchmark problems show that, in the DNS case, the
proposed method allows to correctly reproduce relevant features of variable
density flows with gravity. Moreover LES results highlight the excessively high
dissipation of the Smagorinsky model with respect to the Germano dynamic
procedure, providing a first indication of the superiority of dynamic models in
the context of gravity currents.
