Turbulence at the exascale: application to wind energy, green aviation, air quality and net-zero combustion

Fluid flows relevant to scientists and engineers are typically “turbulent”; turbulence is the rule, not the exception. To date, a complete theory of fluid flow phenomena is still missing because of the complexity of the full equations describing the motion of a fluid. Their understanding and control is however crucial to improve technologies especially with minimal ecological impact as well as to anticipate events, in many areas ranging from engineering applications (e.g. industrial process, propulsion and power generation, car and aircraft design) to environmental sciences and technologies (e.g., air quality, weather forecasting, climate predictions, flood disasters monitoring).

This project brings together communities from the UK Turbulence Consortium (UKTC) and the UK Consortium on Reacting Flows (UKCRF) to ensure a smooth transition to exascale computing, with the aim to develop transformative techniques for future-proofing their production simulation software ecosystems dedicated to the study of turbulent flows.

Understanding, predicting and controlling turbulent flows is of central importance and a limiting factor to a vast range of industries. Many of the environmental and energy-related issues we face today cannot possibly be tackled without a better understanding of turbulence.

This project is aiming at re-engineering and extending the capabilities of four production and research flow solvers for exascale computing: XCOMPACT3D, OpenSBLI, UDALES and SENGA+. These open-source, well-established, community flow solvers are based on finite-difference methods on structured meshes and will be developed to meet the challenges associated with exascale computing while taking advantage of the significant opportunities afforded by exascale systems. A key aim of this project is to leverage the well-established Domain Specific Language (DLS) framework OPS and the 2DECOMP&FFT library to allow XCOMPACT3D, OPENSBLI, UDALES and SENGA+ to run on large-scale heterogeneous computers. OPS was developed in the UK in the last ten years and it targets applications on multi-block structured meshes. It can currently generate code using OPENCUDA, OPENACC/OPENMP5.0, OPENCL, SYCL/ONEAPI, HIP and their combinations with MPI.

The OPS DSLs’ capabilities will be extended in this project, specifically its code-generation tool-chain for robust, fail-safe parallel code generation. A related strand of work will use the 2DECOMP&FFT a Fortran-based library based on a 2D domain decomposition for spatially implicit numerical algorithms on monobloc structured meshes. The library includes a highly scalable and efficient interface to perform Fast Fourier Transforms (FFTs) and relies on MPI providing a user-friendly programming interface that hides communication details from application developers. 2DECOMP&FFT will be completely redesigned for a use on heterogeneous supercomputers (CPUs and GPUS from different vendors) using a hybrid strategy.

The project combines exascale-ready coupling interfaces, UQ capabilities, I/O & visualisation tools to our flow solvers, as well as machine learning based algorithms. This is done in collaboration with several of the recently funded ExCALIBUR cross-cutting projects. The project focuses on four high-priority use cases (one for each solver), defined as high quality, high impact research made possible by a step-change in simulation performance. The use cases are targeting wind energy, green aviation, air quality and net-zero combustion. Exascale computing will be a game changer in these areas and will contribute to make the UK a greener nation (The UK commits to net zero carbon emissions by 2050). The use cases will be used to demonstrate the potential of the re-designed flow solvers based on OPS and 2DECOMP&FFT, for a wide range of hardware and parallel paradigms.

  • A high-fidelity simulation of a full-scale offshore wind farm during operation, within the Xcompact3d framework,
  • A high-fidelity simulation of a NACA0012 airfoil with shock-capturing at high-speed, within the OpenSBLI framework.
  • A high-fidelity simulation of the flow over London using realistic geometry with realistic atmospheric information, within the uDALES code
  • A high-fidelity simulation of turbulent premixed swirl flames involving High Hydrogen Content (HHC) fuels and premixed flame-wall interaction in turbulent boundary layers for rich hydrogen-air mixtures, within the SENGA code

Outreach activities

Web page for the DDWG

Podcast “Turbulence at the exascale”

Online talks about turbulence simulations

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