Research Group of Prof. Dr. M. Griebel
Institute for Numerical Simulation


A Parallel 3D Free Surface Flow Solver




NaSt3DGPF is an implementation of a solver for the incompressible Navier-Stokes equations in three dimensions. It allows the realistic simulation of two-phase flows with free surfaces. NaSt3DGPF exhibits the following features:
  • Simulation of two-phase flow is implemented with a level-set approach
  • Surface tension forces are implemented with the continuum surface force method
  • Simulation of turbulence is based on a large-eddy approach (Smagorinsky model)
  • Convective terms can be discretized with higher order ENO and WENO schemes
  • spatial discretization by 2nd order finite differences on a rectangular, non-uniform, staggered mesh
  • convective term: higher order upwind schemes (VONOS, SMART), central differences (2nd order), simple upwind (1st order)
  • 2nd order Adams-Bashforth scheme for the time discretization
  • boundary conditions: slip, no slip, periodic, inflow, outflow (Neumann, convective, natural)
  • (passive) advection-diffusion transport model for concentration of species
  • Boussinesq advection-diffusion transport model for temperature
  • handling of complex geometries by a simple cell decomposition/enumeration technique
  • BiCGStab and SOR iterative solver for pressure Poisson equation (lexicographical, red-black, colored red-black)
  • parallelization by means of 3D domain decomposition with good communication/work ratio heuristics
  • parallelization based on MPI
  • implemented in C++
  • various import/export formats, including architecture independent ones and for the VTK graphics library
  • macro language for easy problem description
Much emphasis is laid on the point that also complex problems, such as flows around complicated geometries, can be defined in a clear and easy way to obtain numerical results rapidly. To this end, there is a simple macro-language with a few but powerful and meaningful key-words to describe the flow configuration. This allows the user to
  • build complex geometries by union, intersection, subtraction of CSG (Constructive Solid Geometry) primitives using shape parameters independent on the discretization
  • describe the computational mesh in a simple way
  • define various parameters, e.g. Reynolds number, stopping value for iterative solver, upwind parameter, etc.
Have a look at the Gallery for movies of simulation results obtained with NaSt3DGPF.
A list of projects which use NaSt3DGPF as the primary toolkit for numerical simulation of two-phase flow is available here.


For non-profit usage, the software package NaSt3DGPF in its basic version can be obtained here after registration. The full package can be licensed on an individual basis. Please contact us for further details.


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