Adaptive software for high-fidelity simulations of multi-phase turbulent reacting flows

该项目致力于基于自适应网格细化(AMR)的新一代完全并行计算流体动力学(CFD)程序HAMISH的开发、验证和文档编制，该程序将实现对先进的湍流反应流动的高保真直接数值模拟(DNS)，如火焰-壁面相互作用、局部点火和包括雾化过程的液滴燃烧。由于其高昂的计算成本，此类模拟目前无法在不限制简化的情况下实现。AMR用于可压缩湍流反应流动的大规模高度并行模拟是一项重要的新功能，它将在计算经济性方面为涉及薄流体-机械结构的问题提供重大好处，例如火焰-壁面相互作用中火焰和边界层的分辨率，喷雾燃烧中雾化的液滴表面，局部强制点火中的冲击波等。由于固定的全局网格的计算成本过高，这些结构在以前的工作中被忽略或严重简化，从而限制了模拟的有效性。因此，AMR将为湍流反应流动的计算分析提供一个阶梯变化的能力，并将提供数据的详细物理信息的程度，这是目前使用现有CFD程序模拟无法获得的。建议的软件将根据从经过验证的均匀网状DNS代码SENGA2获得的结果进行验证，该代码已经移植到Archer，目前被英国湍流反应流联盟(UKCTRF)的成员广泛使用。新开发的代码Hamish不仅将被移植到Archer上，而且还将为支持加速器的体系结构做好准备，这要归功于OpenMP 4.5，它将支持针对POWER8集群的Openacc。作为该项目的一部分，将在代码的每个新版本中制作一份详细的用户指南。本用户指南将与代码的开放源码版本以及有关代码验证和用户教程的相关文档一起在网站上公开下载。

This project focuses on the development, validation and documentation of a next-generation fully parallelised computa-tional fluid dynamics (CFD) code called HAMISH based on adaptive mesh refinement (AMR) which will enable high-fidelity Direct Numerical Simulations (DNS) of advanced turbulent reacting flows such as flame-wall interaction, localised ignition, and droplet combustion including atomisation processes. Such simulations cannot be achieved at present without limiting simplifications due to their prohibitive computational cost. AMR for large-scale highly-parallel simulations of compressible turbulent reacting flows is a significant new functionality which will offer major benefits in terms of computational economy for problems involving thin fluid-mechanical structures, e.g. resolution of both the flame and the boundary layer in flame-wall interaction, droplet surfaces in atomisation in spray combustion, shock waves in localised forced ignition, etc. Such structures have either been ignored or simplified severely in previous work due to the prohibitive computational cost of fixed global meshes, thus limiting the usefulness of the simulations. Hence AMR will offer a step-change in capability for the computational analysis of turbulent reacting flows, and will provide data with the degree of detailed physical information which is not currently available from simulations using existing CFD codes. The proposed software will be validated with respect to the results obtained from the well-proven uniform-mesh DNS code SENGA2, which has already been ported to ARCHER and is currently widely used by members of the UK Consortium on Turbulent Reacting Flows (UKCTRF). The newly developed code, HAMISH, will not only be ported to ARCHER, but also be prepared for architectures supporting accelerators thanks to OpenMP 4.5, which will support OpenACC, targeting a POWER8 cluster. As a part of this project, a detailed user guide will be produced at each new release of the code. This user guide will be made available on a website for public download along with the open-source version of the code and the associated documentation on code validation and user tutorials.