Compressible flow

Nektar++ includes a solver for simulating the dynamics of compressible inviscid/viscous flow on unstructured two-dimensional and three-dimensional meshes. Specifically, the solver solves two system of equations: Euler equations; Navier-Stokes equations. The systems are provided with a comprehensive set of boundary conditions (1) for specifying inflow/outflow variables as well as wall conditions. In both the systems appropriate techniques for […]

Nektar++ on the Imperial College HPC cluster

Nektar++ on the Imperial College HPC cluster

Imperial College’s HPC system contains computing resources suitable for a broad range of jobs. Node sizes and interconnects therefore vary. This cluster is useful for serial runs, small and large parallel runs, parameter sweep studies, etc. There are also some dedicated private queues which some users may have access.

On the Connections Between Discontinuous Galerkin and Flux Reconstruction Schemes: Extension to Curvilinear Meshes

On the Connections Between Discontinuous Galerkin and Flux Reconstruction Schemes: Extension to Curvilinear Meshes
DOI: 10.1007/s10915-015-0119-z/fulltext.html
Abstract: This paper investigates the connections between many popular variants of the well-established discontinuous Galerkin method and the recently developed high-order flux reconstruction approach on irregular tensor-product grids.

Dealiasing techniques for high-order spectral element methods on regular and irregular grids

Dealiasing techniques for high-order spectral element methods on regular and irregular grids
DOI: 10.1016/j.jcp.2015.06.032
Abstract: High-order methods are becoming increasingly attractive in both academia and industry, especially in the context of computational fluid dynamics. However, before they can be more widely adopted, issues such as lack of robustness in terms of numerical stability need to be addressed, particularly when treating industrial-type problems where challenging geometries and a wide range of physical scales, typically due to high Reynolds numbers, need to be taken into account.

Linear dispersion-diusion analysis and its application to under-resolved turbulence simulations using discontinuous Galerkin spectral/hp methods

Linear dispersion–diffusion analysis and its application to under-resolved turbulence simulations using discontinuous Galerkin spectral/hp methods
DOI: 10.1016/j.jcp.2015.06.020
Abstract: We investigate the potential of linear dispersion–diffusion analysis in providing direct guidelines for turbulence simulations through the under-resolved DNS (sometimes called implicit LES) approach via spectral/hp methods. The discontinuous Galerkin (DG) formulation is assessed in particular as a representative of these methods. We revisit the eigensolutions technique as applied to linear advection and suggest a new perspective to the role of multiple numerical modes, peculiar to spectral/hp methods.

Triple-deck and direct numerical simulation analyses of high-speed subsonic flows past a roughness element

Triple-deck and direct numerical simulation analyses of high-speed subsonic flows past a roughness element
DOI: 10.1017/jfm.2015.281
Abstract: This paper is concerned with the boundary-layer separation in subsonic and transonic flows caused by a two-dimensional isolated wall roughness. The process of the separation is analysed by means of two approaches: the direct numerical simulation (DNS) of the flow using the Navier–Stokes equations, and the numerical solution of the triple-deck equations.

Nektar++ on ARCHER

Nektar++ on ARCHER

The ​ARCHER national supercomputer is intended for very large-scale computations and is the successor to ​HECToR. These instructions are preliminary in nature and an up-to-date version of the master branch is required as support for the compilation environment has only been added recently.

A Guide to the Implementation of Boundary Conditions in Compact High-Order Methods for Compressible Aerodynamics

A Guide to the Implementation of Boundary Conditions in Compact High-Order Methods for Compressible Aerodynamics
DOI: 10.2514/6.2014-2923
Abstract: The nature of boundary conditions, and how they are implemented, can have a significant impact on the stability and accuracy of a Computational Fluid Dynamics (CFD) solver. The objective of this paper is to assess how different boundary conditions impact the performance of compact discontinuous high-order spectral element methods (such as the discontinuous Galerkin method and the Flux Reconstruction approach), when these schemes are used to solve the Euler and compressible Navier-Stokes equations on unstructured grids.

Nektar++ on IDRIS (France)

The following is the script used to configure Nektar++ 3.4 on IDRIS (large HPC cluster in France). This script must be lauched from a directory containing nektar++-3.4.0.tar.gz and ThirdParty-3.4.0.tar.gz. ThirdParty In order to build ThirdParty-3.4.0.tar.gz, follow these steps from an internet-enabled computer: Nektar++ Then do the following: