Interscale Turbulence-Chemistry Dynamics with Reduced Basis Representations
Abstract
Key results of the project include the development of a new periodization procedure to remove nonphysical content from bounded Fourier Transforms (FTF) of non-periodic signals, identification of Fourier-physical space coherent structures in flame-vortex interactions relevant to turbulent premixed flames, identification of dynamically-dominant inter-scale couplings in the advection terms and chemical reaction rates, assessment of disparities in estimating the filtered chemical reaction rates using LES-filtered thermochemical quantities, and quantification of structures of local subfilter scale species concentrations surrounding flame fronts in turbulent premixed flames. Results from each of these studies are summarized next. Because our study centers on scale-based decomposition of the key dynamic variables within the large-eddy simulation framework, decompositions such as proper orthogonal decomposition and dynamic mode decomposition are not useful for our needs. We choose the multidimensional Fourier decomposition fortwo primary reasons. Firstly, the Fourier transform (FTF) is useful to decompose multidimensional multiscale analytic functions into scale-based series of complex exponentials that are mathematically convenient for scale-based analysis in elemental form. More importantly, however, the Fourier transform produces the most elemental description of the advective and chemical nonlinearities in the equations of motion as linear sums of nonlinear terms, each of which represents an elemental interaction among a few Fourier modes. These mathematically elegant elemental forms within the Fourier spectral description of nonlinear interscale interactions may be rearranged in order to down-select a small percentage of the most dominant nonlinear interscale couplings that contribute to the evolution of resolved-scale momentum, thermal energy and species concentration predicted in LES of flame-turbulence interactions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 07, 2021
- Accession Number
- AD1230626
Entities
People
- James G. Brasseur
- Yuan Xuan
Organizations
- Pennsylvania State University