Broadband Reconstruction of Inhomogeneous Turbulence Using a Combination of Data and Physics Driven Modeling

Speaker: Aditya Ghate, Science and Technology Corporation/NASA Ames Research Center
December 20, 2022

Presentation

Abstract

A new methodology to construct three-dimensional, temporally stationary but spatially inhomogeneous, incompressible turbulence is presented. The method combines the use of data-driven identification of a global basis for the fluctuation field to identify and isolate large-scale coherent motions of the flow, together with a physics-based enrichment algorithm using spatiotemporally localized wavepackets that capture the inertial subrange turbulence. These wavepackets have special properties in that they can represent large range of scales in a compressed manner and accurately capture the inter-scale physics of the energy cascade via a specific variant of the Rapid Distortion Theory (RDT) that uses WKB-asymptotics. To demonstrate the approach, we consider two distinct problems: a) wake turbulence of a dragging actuator disk impinged by homogeneous isotropic turbulence, and b) inhomogeneous wake of a realistic landing gear (LAGOON) geometry. The reconstructed flow field has single- and two-point correlations that are consistent with the reference high-resolution simulation data. This fusion of data-driven and physics-based methods enables a statistically correct reconstruction of broadband turbulent flows at a fraction of computational cost compared to a conventional scale resolving simulation method such as Large Eddy Simulation, as well as in other applications such as generation of statistically consistent inflow boundary conditions.

Biography

Aditya Ghate joined the Computational Aerosciences Branch of the NASA Advanced Supercomputing (NAS) Division at NASA Ames Research Center in 2018. His research within the Launch, Ascent, and Vehicle Aerodynamics (LAVA) group involves development Large Eddy Simulations (LES) tools for prediction of complex flow physics seen in a large array of engineering applications. Aditya obtained his PhD in Aeronautics & Astronautics from Stanford University in 2018 where his thesis work focused on theory and modeling on subfilter-scale turbulence in LES.

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