nekRS is an open-source based Navier Stokes solver using the spectral element method. It is build on top of the discretization library libParanumal targeting modern processors and accelerators including multi/many-core CPU and GPU platforms using OCCA.

Capabilities:

• Incompressible Navier Stokes
• CG-SEM using hexaheadral elements
• Inlet, outflow, wall, slip and periodic boundary conditions
• Constant density and viscosity
• Fixed timestep 2nd order BDF + EXT/OIFS
• Dealiasing and high-pass filter relaxation term regularization
• MPI+X hybrid parallelism supporting serial (CPU) and CUDA
• Interface to Nek5000

Note, the code is an early prototype so it's very likely that you run into undiscovered issues. Moreover it's evolving quickly so things might change from one version to another without being backward compatible.

Requirements:

• POSIX compilant OS
• GNU Fortran and C Compiler version 6.2 or later
• MPI-3.1 or later
• CMake version 3.1 or later
• Login shell is bash or zsh

Download the latest release tarball

wget https://github.com/Nek5000/nekRS/releases/download/v19.0/nekRS-v19.0.tar.gz 
tar -zxf nekRS-v19.0.tar.gz 

or clone our GitHub repository:

git clone https://github.com/Nek5000/nekRS.git

To install the code just run:

cd nekRS
./makenrs

Please edit the make script to customize build settings.

Assuming you run bash, add the following line to your $HOME/.bash_profile:

source <your install path>/bin/nekrs.bashrc

then type source $HOME/.bash_profile in the current terminal window.

cd $NEKRS_EXAMPLES/ethier
nrsmpi ethier 2 # run on two MPI ranks

• Only the basic functionality of Nek5000 is available
• Kernels are optimized primarily for latest NVIDIA GPUs

Our project is hosted on GitHub and everbody is welcome to become a part of it. If you are planning a large contribution, we encourage you to discuss the concept here on GitHub and interact with us frequently to ensure that your effort is well-directed.

If you run into problems compiling, installing, or running nekRS, please send a message to the User's Group mailing list. Please sign up to post your questions, concerns or suggestions.

nekRS is hosted on GitHub and all bugs are reported and tracked through the Issues feature on GitHub. If you are having trouble installing the code or getting your model to run properly, you should first send a message to the User's Group mailing list.

nekRS is released under the BSD 3-clause license (see the LICENSE file). All new contributions must be made under the BSD 3-clause license.