Girish Mahajan (Editor)

Nektar

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Stable release
  
4.4.0 / March 2017

License
  
MIT License,

Written in
  
C++

Initial release
  
4th May 2006 (10 years)

Operating system
  
Unix/Linux/OS X/Windows,

Type
  
Spectral element method, Hp-FEM, Computational fluid dynamics,

Nektar++ is a spectral/hp element framework designed to support the construction of efficient high-performance scalable solvers for a wide range of partial differential equations (PDE). The code is released as open-source under the MIT license. Although primarily driven by application-based research, it has been designed as a platform to support the development of novel numerical techniques in the area of high-order finite element methods.

Contents

Nektar++ is modern object-oriented code written in C++ and is being actively developed by members of the SherwinLab at Imperial College London (UK) and Kirby's group at the University of Utah (US).

Capabilities

Nektar++ includes the following capabilities:

  • One-, two- and three-dimensional problems;
  • Multiple and mixed element types, i.e triangles, quadrilaterals, tetrahedra, prisms and hexahedra;
  • Both hierarchical and nodal expansion bases with variable and heterogeneous polynomial order between elements;
  • Continuous Galerkin, discontinuous Galerkin, hybridizable discontinuous Galerkin and flux reconstruction operators;
  • Multiple implementations of finite element operators for efficient execution on a wide range of CPU architectures;
  • Comprehensive range of explicit, implicit and implicit-explicit (IMEX) time-integration schemes;
  • Preconditioners tailored to high-order finite element methods;
  • Numerical stabilization techniques such as dealiasing and spectral vanishing viscosity;
  • Parallel execution and scalable to thousands of processor cores;
  • Pre-processing tools to generate meshes, or manipulate and convert meshes generated with third-party software into a Nektar++-readable format;
  • Extensive post-processing capabilities for manipulating output data;
  • Cross platform support for Linux, Mac OS X and Windows;
  • Support for running jobs on cloud computing platforms via the prototype Nekkloud interface from the libhpc project;
  • Wide user community, support and annual workshop.
  • Stable versions of the software are released on a 1-month basis and it is supported by an extensive testing framework which ensures correctness across a range of platforms and architectures.

    Other capabilities currently under active development include p-adaption, r-adaption and support for accelerators (GPGPU, Intel Xeon Phi).

    Application domains

    The development of the Nektar++ framework is driven by a number of aerodynamics and biomedical engineering applications and consequently the software package includes a number of pre-written solvers for these areas.

    Incompressible flow

    This solver time-integrates the incompressible Navier-Stokes equations for performing large-scale direct numerical simulation (DNS) in complex geometries. It also supports the linearised and adjoint forms of the Navier-Stokes equations for evaluating hydrodynamic stability of flows.

    Compressible flow

    External aerodynamics simulations of high-speed compressible flows are supported through solution of the compressible Euler or Navier-Stokes equations.

    Cardiac Electrophysiology

    This solver supports the solution of the monodomain model and bidomain model of action potential propagation through myocardium.

    Other application areas

  • shallow water equations;
  • reaction-diffusion-advection problems;
  • pulse wave propagation solver for modelling arterial networks;
  • acoustic perturbation equations;
  • linear elasticity equations.
  • License

    Nektar++ is free and open source software, released under the MIT license.

    Free and open-source software

  • Nek5000 (GPL)
  • Advanced Simulation Library (AGPL)
  • Code Saturne (GPL)
  • FEATool Multiphysics
  • Gerris Flow Solver (GPL)
  • OpenFOAM (GPL)
  • SU2 code (LGPL)
  • Proprietary software

  • ADINA CFD
  • ANSYS CFX
  • ANSYS Fluent
  • COMSOL Multiphysics
  • Pumplinx
  • STAR-CCM+
  • KIVA (software)
  • RELAP5-3D
  • References

    Nektar++ Wikipedia