Fluids York etal

TN-01_Task01Environments

This document describes activities from January to March 2021, to coordinate community activities under the ExCALIBUR-Neptune project. The deliverable for this work package was to set up the development environment (version control, continuous development/integration, automated testing and documentation services, coding standards).

TN-02_Task11EllipticSolverTests

This report gives a brief overview of the origin of elliptic problems in plasma physics models, and the tokamak geometry they are solved in. Drawing mainly on experience with BOUT++, approaches to testing of both correctness and performance, and the pros and cons of them are discussed.

TN-03_Task12EllipticSolverImplementation

Reference elliptic solver implementations in BOUT++ are described, along with the techniques which use simplified methods to effectively precondition more complex problems. Implementations include PETSc-based solvers and a new Hypre implementation.

TN-04_Task211DFluidModelTests

This deliverable defines Test cases for a 1D fluid solver with UQ and realistic boundary conditions, relevant to the Neptune use case.

TN-05_ExcaliburNeptuneBoutMultifluidImplementation

This report explores the use of BOUT++ as a platform to test design patterns that enable plasma simulations models to be extended from single ion species to multiple species. The aim is to evaluate code designs, explore Domain Specific Languages (DSLs) for specifying complex multi-fluid models, and provide a platform for further development.

TN-06-1_Task14Preconditioning2DEllipticSolvers

Explores different preconditioner approaches for a range of problems, emphasizing integration into libraries such as PETSc and testing on realistic problems. Discusses the benefits of using HYPRE preconditioners available in BOUT++.

TN-07-1_ExcaliburNeptuneImplementation1DFluidSolverRealisticBoundaryConditions

This report summarizes the implementation of a 1D model SD1D including fluid neutrals and realistic boundary conditions for a system (2-3). Selected test cases from task 83-2.1 are also discussed.

TN-08-1_ExcaliburNeptuneTask24NonIntrusiveUqBout1DFluidSolver

In this report, we summarize experience gained in the application of non-intrusive uncertainty quantification (UQ) to a sample test case from the SD1D test cases set out in task 83-2.1. This provides a test ground for the practical aspects of UQ for realistic plasma simulations and showcases the easyvvuq package to facilitate the construction of UQ workflows.

TN-09-1_Task8341TestCases1DMultispeciesPlasmaModel

Outlines test cases for a 1D multispecies plasma model given by system 2-5 of reference [1]. The tests build on the tests for the single plasma fluid model and cover three broad areas: separate ion and electron temperatures, enhanced neutral gas models including different excited states of hydrogen, and impurity species.

TN-10-1_DevelopmentPerformanceTestingAggregationToolNeptuneProxyApps

This report outlines the requirements and design of a software framework for the automated performance testing and performance regression analysis of git-managed software, specifically for the proxy apps developed as part of the ExCALIBUR NEPTUNE project.

TN-11-1_ExcaliburNeptuneConsiderations1D1V

This report documents some of the work around tasks 3.1, 3.2 and 3.3 looking at the Vlasov-Ampere system in a periodic 1D+1V domain. A number of test cases are defined and some of the considerations around phase-space representations and time integration are discussed.

TN-12-2_EllipticSolversWithinNektar

This report focuses on the performance of the elliptic solver within Nektar++ and its scaling in the limit of large processor counts. The solver has been used within the anisotropic diffusion solver provided under project 2048465.

TN-13-2_Spatially2DPlasmaModelIncorporatingVelocitySpaceEffects

This report outlines potential routes for implementation of the system 2-6 equations within the Nektar++ framework. It highlights steps required, where improvements should be made within Nektar++ to enable future implementation.

TN-14-1_ExcaliburNeptuneDslCodeDesignPatternNeptune

Discusses approaches to code design and the adoption of domain specific languages (DSLs) for multi-species simulations in the BOUT++ and Nektar++ solvers.

TN-15-2_ExcaliburNeptunePerformanceConsiderationsNonIntrusiveUncertaintyQuantificationInf

This report summarizes performance considerations relevant to the use of non-intrusive uncertainty quantification tools such as the easyvvuq package. It explores minimizing the number of simulations, effective use of workflow management tools, and the number of moments required for converged uncertainty measures near the boundary.

TN-16-1_ExcaliburNeptuneCommunityEnvironment

This report discusses ExCALIBUR-Neptune community activities from October 2021 to October 2022 and the state of the community environment at the date of this report. It covers numerous workshops and events hosted by project partners, the current digital tools for community interactions, and suggestions to enhance the digital environment.

TN-17_ProgressImplementationSystem26EquationsWithinNektarFramework

This report briefly outlines the initial efforts on implementing the system 2-6 equation set within the Nektar++ framework. It discusses changes made to the equation set since the previous deliverable, and outlines a prototype solver for a simplified set of equations, as well as the future development pathway for system 2-6.