Dyniso solves the incompressible Navier-Stokes equations in a box with the intent of simulating the decay of homogeneous, isotropic turbulence.

For more information see Dyniso wiki.

Assuming a Linux system with the Intel compilers in your path and a threaded FFTW 2.1.5 available at: $(HOME)/local/fftw-thread simply do:

cd src
make opt

Note, if your compilers are not available using different names you may need to explicitly tell make where to find them, such as:

env CC=gcc-9 FC=gfortran-9 make opt

Dyniso has not been updated yet to work with FFTW3.

To execute dyniso, you redirect a namelist input file, such as:

./dyniso.exe < test.inp

to select the number of OpenMP threads, do:

env OMP_NUM_THREADS=4 ./dyniso.exe < test.inp

The code will output a number of files including:

1. Time statistics in stat?.dat
2. Spectra at selected timesteps in spectra.*
3. Plot3d visualization files in out.{xyz,q}
4. Use Paraview to visuzlize Plot3d files

1. The Plot3d files are in Fortran unformated (not C-binary)
2. Performance is highly dependant on the FFT library used. If using FFTW v2 you should read:
   FFTW Documentation
3. Note that FFTW must be build with --enable-threads and --with-openmp
4. Dyniso does not work with FFTW v3, yet...

S. Scott Collis
[email protected]