README file for the Simson code (on public github)

Simson is a code containing a pseudo-spectral solver for the incompressible Navier-Stokes equations together with selected pre- and postprocessing tools. Both direct numerical simulations (DNS) and large-eddy simulations (LES) are supported. This version does only include one-dimensional parallelisation.

See COPYRIGHT file.

• bla - Main program
• bls - Program to generate initial velocity (with or without heat) fields
• common - Common subroutines between programs
• doc - Documentation
• examples - Example flow cases
• matlab - Matlab scripts
• pxyst - Program to do xy statistics plotting
• rit - Program to plot solutions from complete velocity fields
• lambda2 - Program co compute lambda2, Q for visualisation

• COPYRIGHT - Copyright and contact information document
• README - This document
• todo.txt - A text file including things to correct/fix/add etc.

Compile using make in each subdirectory the various codes. Make sure to adapt par.f in each subdirectory. For bla there are additional compilation options such as omp, mpi and arch. Concretely, in the directories bls, pxyst, lambda2, rit, just type

make In the bla directory, type for an OpenMP parallel case make omp=yes

As discussed, before starting to compile the code the resolution and some other compile-time parameters have to be chosen for the flow problem that you want to run. These parameters are fetched from the par.f file located in the same directory as the application that is about to be compiled.

For more details on how to install, compile and run the code read the manual located in the doc directory. Also view the examples directory.

Usually, the stacksize of the shell needs to be extended, e.g. using

ulimit -s unlimited

The visualisation codes typically require an xterm. Thus run rit, pxyst, etc. from an xterm (rather than the built in terminal).

A good starting point is the example case "channel" in the examples directory. A step by step readme file guides you through running the first case.