Accelerating Manycore Fluid Flow Predictions Including Wave/Ship Motions Using Parareal

百亿亿级高性能计算的趋势表明，未来将以低成本提供大量的计算资源，但要充分利用这些新兴的多核硬件系统，需要新的软件设计和并行化策略。在过去的六年里，申请人领导了一种名为EXN/Aero的多核计算流体动力学（CFD）代码的开发，与使用空间域分解获得的传统CPU解决方案相比，该代码现在展示了显着的解决方案加速（使用gpu）。EXN/Aero的发展还包括一种称为平行的组合时空并行计算方法。在这里，域分解包括空间和时间，并且是百亿亿次计算中的一个新兴研究领域，因为它提供了一种在高度并行应用程序受内存限制时减少计算时间的方法。然而，需要改进高雷诺数和多物理场CFD应用的方法。拟议研究的选择应用是在环境和船舶/海底洋流领域。在这些区域建立一套高效的三维非定常湍流CFD模型对于全面的声源建模非常重要，包括后续广泛的特征研究。申请人已经在加拿大国防研究与发展部的潜艇项目（开发包括EXN/Aero在内的一系列CFD模拟能力）中工作了多年，因此将其扩展到船舶上是很自然的。特别是，该建议将重点放在发展船舶模拟的平行方法的目标上，包括波浪，船舶运动和推进（包括空化）的重要耦合。所有这些方面都是重要的，当耦合时，预测高度湍流的流动环境噪声源产生。这项研究将使加拿大工业界和政府能够利用未来的CFD超级计算技术，这对开发复杂系统（如船舶和潜艇平台）以及环境流（如潮汐能开发）至关重要。

Exascale high-performance computing trends point to substantial computing resources at a low cost moving into the future, but new software designs and parallelization strategies are required to take full advantage of these emerging manycore hardware systems. Over the past six years, the applicant has led the development of a manycore Computational Fluid Dynamics (CFD) code called EXN/Aero that is now demonstrating significant solution speed-up (using GPUs) versus traditional CPU solutions obtained with spatial domain decompositions. The EXN/Aero development has also included a combined space-time parallel computing approach called parareal. Here, the domain decomposition includes both space and time, and is an emerging research area in exascale computing since it provides a way to reduce computing time when a highly parallel application is memory-bound. There is, however, a need to refine the methodology for high-Reynolds number and multi-physics CFD applications. The applications of choice for the proposed research is in the area of environmental and ship/submarine ocean flows. Building an efficient set 3D unsteady turbulent flow CFD models in these areas is important for comprehensive acoustic source modeling, including subsequent input into a wide range of signatures studies. The applicant has worked for a number of years with Defense Research and Development Canada on their submarine program (developing a range of CFD simulation capabilities including EXN/Aero) and the extension to ships is therefore a natural one. In particular, the proposal will focus on objectives that develop the parareal method for ship simulations that include the important couplings of waves, ship motion and propulsion (including cavitation). All of these aspects are important, when coupled, to predicting the highly turbulent flow environment from which noise sources arise. The research will allow Canadian industry and government to tap into future CFD supercomputing technologies which will be essential to developing complex systems such as ship and submarine platforms, and environmental flows such as that for tidal energy development.