OpenFOAM has an extensive range of features to simulate anything from
turbulent flows in automotive aerodynamics, to fires and fire
suppression in buildings, involving combustion, chemical reactions,
heat transfer, liquid sprays and films. It includes tools for meshing
in and around complex geometries (e.g. a vehicle), and for data
processing and visualisation, and more. Almost all computations can be
executed in parallel as standard to take full advantage of today's
multi-core processors and multi-processor computers.

Optional dependency: graphviz (for documentation with graphs)

You can build with multiple jobs by setting the MAKEFLAGS environment
variable (e.g. export MAKEFLAGS="-j$(nproc)" at bash prompt).