NIP2Eq

Movie generation (python/nip2eq_movie.py)

The solver's amovout/umovout subroutines (in src/mod_inout.f90) write the void fraction a and velocity u fields to output1.dat/output2.dat (numerical) and output5.dat/output6.dat (exact solution, if any) every print freq timesteps, in a plain-text, Tecplot-style ASCII format: each frame is a VARIABLES/ZONE/SOLUTIONTIME header followed by the data points for that frame, with frames appended back-to-back.

python/nip2eq_movie.py reads that format directly (no Tecplot required) and renders it as a movie with matplotlib:

python3 python/nip2eq_movie.py <case_dir> -o movie.mp4 [--fps N] [--stride N] [--no-exact]

• <case_dir> is a directory containing output1.dat/output2.dat (and optionally output5.dat/output6.dat), e.g. a benchmark or verification case directory after running nip2eq.x.
• -o/--out sets the output file (.mp4 needs ffmpeg, .gif needs Pillow); omit it to show the animation interactively instead.
• --fps sets the frame rate (default 10).
• --stride uses every Nth frame, for faster/coarser previews.
• --no-exact skips overlaying the exact solution even if present.

The exact-solution overlay is skipped automatically when aex/uex are identically zero (i.e. no exact solution exists for the problem, e.g. the water-faucet case).

Requires numpy and matplotlib (and ffmpeg for .mp4 output).

old note

This was an old note that I left to myself when I wrote this code back in 2012 or so:

need to add: if(bc = periodic) then call bndry affter the source call then wrap all the "update" terms into a subroutine need to apply bndry after every exact call (see exact subroutine, all calls need to be removed) put all subroutines into a seperate file that will get cat'd into a large otherwise empty module