Dynamical systems analysis of scale interactions in wall bounded turbulent shear flows
Abstract
There is a growing body of evidence that high Reynolds number wall turbulence is organised into a hierarchy of self similar, self sustaining coherent structures, the size of which is proportional to their distance from the wall. Despite the important progress made recently, most of previous studies have only focused on the statistics and dynamics of energy containing structures at a given length scale. However, given the strongly nonlinear nature of the Navier Stokes equations, these energy containing structures emerging at different scales would interact with each other. This scale interaction across many scales throughout the entire wall normal locations currently remains very poorly understood, and, in particular, the presence of a continuum of scales has inhibited any analysis of the temporal dynamics of the scale interaction processes. Motivated by the recent successes of the dynamical systems analysis of single scale turbulence, the goal of this proposal is to extend this approach to describe the temporal dynamics of a minimal multi scale (two scale) system in the near wall region, with a particular focus on understanding the `dynamical interactions between the energy containing structures of different scales. This proposal sets out two work packages, which have not been explored previously, based on the state of the art understanding of wall turbulence: 1) The construction of the state space of a scale interaction system; 2) The identification of the reduced order dynamics in scale interactions. The outcome of this proposal will provide insight into the fundamental physical processes of the collective dynamics of the energy containing coherent structures of high Reynolds number wall turbulence.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501917021
Entities
People
- Yongyun Hwang
Organizations
- Air Force Office of Scientific Research
- Imperial College London
- United States Air Force