AquaTerm is a Mac OS X grahics renderer. It allows command line applications written in ObjC, C, FORTRAN, Lisp, Perl or Python to display vector graphics, text and images using a simple API. Adapters for gnuplot, PGPLOT, and PLplot exists as well.
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.