Internal Report

SIMSON - A Pseudo-Spectral Solver for Incompressible Boundary Layer Flows

Author Document Type Year Download File size
Mattias Chevalier, Philipp Schlatter, Anders Lundbladh, Dan Henningson Technical report 2007 Download 1.1 Mb
ISSN 0348-467X


This report is a part of Simson version 4.0.0, a software package that implements an efficient spectral integration technique to solve the Navier-Stokes equations for incompressible channel and boundary layer fows. The report describes how to configure, compile and install the software. Additionally, an introduction to the theory and the numerical details of the implementation is given. The solver is implemented in Fortran 77/90. The original algorithm reported in Lundbladh et al. (1992a) solved the incompressible Navier-Stokes equations in a channel flow geometry. That algorithm has been reimplemented in a boundary layer version of the code reported in Lundbladh et al. (1999). That allowed simulations of the flow over a flat plate. To do this an artificial free-stream boundary condition was introduced, and for spatial simulations a fringe region technique similar to that of Bertolotti et al. (1992) was implemented. In Simson the channel and boundary layer solvers have been combined together with many different features developed over the years. The code can be run either as a solver for direct numerical simulation (DNS) in which all length and time scales are resolved, or in large-eddy simulation (LES) mode where a number of different subgrid-scale models are available. The evolution of multiple passive scalars can also be computed. The code can be run with distributed or with shared memory parallelization through the Message Passing Interface (MPI) or OpenMP, respectively. The wall-parallel directions are discretized using Fourier series and the wall-normal direction using Chebyshev series. Time integration is performed using a third order Runge-Kutta method for the advective and forcing terms and a Crank-Nicolson method for the viscous terms. The basic numerical method is similar to the Fourier-Chebyshev method used by Kim et al. (1987). Further details about spectral discretizations and additional references are given in e.g. Canuto et al. (1988).