A PENULTIMATE PETASCALE COMPUTATIONAL LABORATORY FOR TURBULENCE AND MAGNETOHYDRODYNAMIC TURBULENCE

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The objective of this project is to use the Blue Waters supercomputer to enable lasting contributions to the study of scale similarity in turbulent flows at high Reynolds number, and of the behavior of turbulent flows subjected to an external magnetic field and solid-body rotation. Advanced post and on-the-fly processing techniques are to be applied to extract unique physical insights from the largest turbulence simulation to date (over half a trillion grid pints) aimed at fine-scale structure, made possible through a priorPRAC allocation. A careful choice of parameters and initial conditions will allow the first numerical simulation of the response of turbulence with a classical inertial range to the forces of electromagnetic induction as well as uniform solid-body rotation. The project is expected to be of great impact for many fields of research such as meteorology, combustion, wind power, where intermittent outbursts of strong turbulence must be considered. Additionally, studying the combined effects of magnetic fields and solid-body rotation on a turbulent flow will provide crucial steps for our understanding how the Earth's magnetic field arises. Furthermore, by providing new data generated from this project, the impact on fundamental turbulence research is likely to be transformative.The search for conclusive results on the problem of refined scale similarity applicable to high Reynolds number turbulent flows in diverse geometries has long been a grand challenge in turbulence theory. The intellectual merit of the proposed research lies in part in the rigorous analysis of high-resolution simulation data that has finally shown promise of enabling a penultimate description in this pursuit. Time-resolved dynamical information on extreme events in connection to vortical structures will in particular be new especially at the high Reynolds number possible on Blue Waters. For magnetohydrodynamic (MHD) turbulence the new simulations are expected to meet the challenge of understanding the flow physics while meeting competing demands for higher Reynolds number, domain size especially along the direction of an imposed magnetic field, and different time scales associated with the strength of the latter. Consideration of the coupling MHD turbulence with solid-body rotation also raises many further complexities, for which the proposed simulations will provide a basic characterization previously not available in the literature. Finally, sustained access to Blue Waters will provide doctoral students in this project with opportunities towards becoming leaders in the next generation of computational scientists.