Enabling hydrodynamics solver for efficient parallel simulations

In this paper we present the parallel solver χnavis, a general purpose solver for Computational Fluid Dynamics (CFD). The solver is based on the finite volume discretization of the unsteady incompressible Navier-Stokes equations; main features include a level set approach to handle free surface flows and a dynamical overlapping grids approach, which allows to deal with bodies in relative motion. The baseline code features a hybrid MPI/OpenMP parallelization, proven to scale when running on order of hundreds of cores (i.e. Tier-1 platforms). This paper deals with latest developments aimed to extend the capabilities of the χnavis software to exploit modern parallel architectures. Scalability properties will be demonstrated for different cases. As example of application, the computation of the flow fields around a submarine in prescribed oscillatory motion and a surface flow around a catamaran in steady drift advancement are presented.