code_saturne is the free, open-source software developed primarily by EDF for computational fluid dynamics (CFD) applications.
It solves the Navier-Stokes equations with scalar transport for 2D, 2D-axisymmetric, and 3D flows, whether steady or unsteady, laminar or turbulent, incompressible, dilatable, or weakly compressible, isothermal or not.
It is based on a finite-volume approach that accepts unstructured meshes with any type of cell (tetrahedral, hexahedral, prismatic, pyramidal, polyhedral...). Most models use co-located cell-centered finite volumes, with work in progress on CDO (compatible discrete operator) numerical schemes.
The code_saturne solver can run on just about any UNIX or Linux type system and processor (including of course x86_64 and various ARM type processors).
Several turbulence models are available, from Reynolds-Averaged models to Large-Eddy Simulation models. In addition, a number of specific physical models are also available as modules: gas, coal combustion, semi-transparent radiative transfer, particle-tracking with Lagrangian modeling, Joule effect, electrics arcs, weakly compressible flows, atmospheric flows, rotor/stator interaction for hydraulic machines.
More details are provided here.