Found these interesting, free Computer Aided Engineering (CAE) software tools, thought I'd start a list. Mostly for Linux, but some for Windows.
Elmer (multiphysics FEA)
Gerris Flow Solver (CFD)
OpenFOAM (CFD, continuum mechanics, thermodynamics, EM fields, ...)
Z88 (FEA, Windows version available)
CAELinux (Linux CAE bundle)
Open CASCADE (Software development platform)
So much software, so little time...