AuthorsM. Mortensen and K. Valen-Sendstad
TitleOasis: A high-level/high-performance open source Navier–Stokes solver
AfilliationScientific Computing, Center for Biomedical Computing (SFF), Scientific Computing
Project(s)Center for Biomedical Computing (SFF)
Publication TypeJournal Article
Year of Publication2015
JournalComputer Physics Communications
Pagination177 - 188

Abstract Oasis is a high-level/high-performance finite element Navier–Stokes solver written from scratch in Python using building blocks from the \{FEniCS\} project ( The solver is unstructured and targets large-scale applications in complex geometries on massively parallel clusters. Oasis utilizes \{MPI\} and interfaces, through FEniCS, to the linear algebra backend PETSc. Oasis advocates a high-level, programmable user interface through the creation of highly flexible Python modules for new problems. Through the high-level Python interface the user is placed in complete control of every aspect of the solver. A version of the solver, that is using piecewise linear elements for both velocity and pressure, is shown to reproduce very well the classical, spectral, turbulent channel simulations of Moser et al. (1999). The computational speed is strongly dominated by the iterative solvers provided by the linear algebra backend, which is arguably the best performance any similar implicit solver using \{PETSc\} may hope for. Higher order accuracy is also demonstrated and new solvers may be easily added within the same framework. Program summary Program title: Oasis Catalogue identifier: AEUW_v1_0 Program summary URL: Program obtainable from: \{CPC\} Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: \{GNU\} Lesser \{GPL\} version 3 or any later version No. of lines in distributed program, including test data, etc.: 3491 No. of bytes in distributed program, including test data, etc.: 266924 Distribution format: tar.gz Programming language: Python/C++. Computer: Any single laptop computer or cluster. Operating system: Any (Linux, OSX, Windows). RAM: a few Megabytes to several hundred Gigabytes Classification: 12. External routines: \{FEniCS\} 1.3.0 (, that in turn depends on a number of external libraries like MPI, PETSc, Epetra, Boost and ParMetis) Nature of problem: Incompressible, Newtonian fluid flow. Solution method: The finite element method. Unusual features: \{FEniCS\} automatically generates and compiles low-level C++ code based on high-level Python code. Running time: The example provided takes a couple of minutes on a single processor.

Citation Key23333