NekRS

At a glance

• Editor score
  Not yet scored
• Pricing
  Free plan
• Best for
  HPC teams running high-order flow simulations
• Free plan
  Yes
• Paid from
  None
• Deployment
  Desktop
• Facts checked
  24 Sep 2026

• Where it wins

  • High-order spectral elements for incompressible and low-Mach flow
  • Supports LES, RANS, moving meshes, overset grids and conjugate heat transfer
  • MPI execution with CUDA, HIP, DPC++ and serial C++ backends

• Where it doesn't

  • Requires a source build and self-hosted deployment
  • Mesh workflows require converted meshes from external tools
  • Focused on incompressible and low-Mach flows

Our verdict on NekRS

NekRS is an open-source computational fluid dynamics solver for teams running high-order flow simulations on high-performance computing systems. It solves incompressible and low-Mach-number Navier–Stokes equations with scalar transport, using high-order curvilinear hexahedral spectral elements. Its capabilities suit simulation groups that need turbulence modeling, moving meshes, overset grids or fluid-solid heat transfer, rather than a general-purpose geometry-to-simulation environment.

The solver combines MPI-based parallel execution with CPU and accelerator backends: CUDA, HIP, DPC++ and serial C++. Modeling options include LES and RANS turbulence models, an arbitrary-Lagrangian-Eulerian moving mesh, a Lagrangian phase model, overlapping overset grids and conjugate fluid-solid heat transfer. VisIt, ParaView and Ascent are listed integrations. This makes NekRS relevant to teams with an established HPC workflow and a need for these specific flow capabilities; it is less suited to buyers seeking broad CAD-driven multiphysics workflows.

NekRS is free and distributed under the BSD 3-Clause license, but it is not a managed service: users build it from source and self-host it on Linux or macOS. Meshes must be provided or converted through NekRS and Nek5000 workflows or other meshing software; built-in meshing and CAD geometry import are not part of its documented scope. Documentation and community support are the listed support channels. Choose NekRS if your team can handle the build and mesh preparation and needs its high-order, parallel solver capabilities. Consider another tool if integrated geometry preparation or a hosted workflow is central to your process.

NekRS pricing

NekRS fact sheet

NekRS integrations

NekRS lists 3 integrations on its own site.

• VisIt
• ParaView
• Ascent

Alternatives to NekRS

• AFAnsys FluentA broad engineering CFD suite with automated meshing, GPU/HPC solving, and Ansys integrations.—
• SimScaleBrowser-based CFD with CAD preparation, cloud computing, APIs, and a free entry plan.4.0
• COMSOL MultiphysicsCFD modeling in a desktop environment built for coupled physics and broader engineering simulation.—

See all NekRS alternatives →

Featured on iTechGuides

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Reviewed by iTechGuides Editors · Editorial team · Updated Sep 2026

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