Spatio-temporal Proper Orthogonal Decomposition of turbulent channel flow
Abstract
An extension of Proper Orthogonal Decomposition is applied to the wall layer of a turbulent channel flow (Re {\tau} = 590), so that empirical eigenfunctions are defined in both space and time. Due to the statistical symmetries of the flow, the igenfunctions are associated with individual wavenumbers and frequencies. Self-similarity of the dominant eigenfunctions, consistent with wall-attached structures transferring energy into the core region, is established. The most energetic modes are characterized by a fundamental time scale in the range 200-300 viscous wall units. The full spatio-temporal decomposition provides a natural measure of the convection velocity of structures, with a characteristic value of 12 u {\tau} in the wall layer. Finally, we show that the energy budget can be split into specific contributions for each mode, which provides a closed-form expression for nonlinear effects.
Keywords
Cite
@article{arxiv.1805.01494,
title = {Spatio-temporal Proper Orthogonal Decomposition of turbulent channel flow},
author = {Srikanth Derebail Muralidhar and Bérengère Podvin and Lionel Mathelin and Yann Fraigneau},
journal= {arXiv preprint arXiv:1805.01494},
year = {2019}
}