Wavefront is a programme for simulating 2D acoustic systems, with a particular emphasis on determining wavefront shapes at the mouths of horns.
It accepts CAD drawings in DXF format and produces animated displays of wave propagation as well as exporting various data as text files.
It is GPL software and runns on Linux and Windows.
A Fast MAC based 3D Free surface fuid solver. Capable also of simulating viscoelastic fluids.Includes also wave equation solver for simulating shallow water phenomena.
NecJGui is an antennas design tool, interface for Numerical Electromagnetic Code. It allows easily making NEC input files, and viewing them in 3D. It also contains a version of the simulator, so it's complete IDE for full-wave EM simulation.