Identifying eigenmodes of averaged small-amplitude perturbations to turbulent channel flow Academic Article uri icon

abstract

  • Eigenmodes of averaged small-amplitude perturbations to a turbulent channel flow which is one of the most fundamental canonical flows are identified for the first time via an extensive set of high-fidelity graphics processing unit accelerated direct numerical simulations. While the system governing averaged small-amplitude perturbations to turbulent channel flow remains unknown, the fact such eigenmodes can be identified constitutes direct evidence that it is linear. Moreover, while the eigenvalue associated with the slowest-decaying anti-symmetric eigenmode mode is found to be real, the eigenvalue associated with the slowest-decaying symmetric eigenmode mode is found to be complex. This indicates that the unknown linear system governing the evolution of averaged small-amplitude perturbations cannot be self-adjoint, even for the case of a uni-directional flow. In addition to elucidating aspects of the flow physics, the findings provide guidance for development of new unsteady Reynolds-averaged NavierStokes turbulence models, and constitute a new and accessible benchmark problem for assessing the performance of existing models, which are used widely throughout industry.

published proceedings

  • Journal of Fluid Mechanics

altmetric score

  • 50.45

author list (cited authors)

  • Iyer, A. S., Witherden, F. D., Chernyshenko, S. I., & Vincent, P. E.

citation count

  • 3

complete list of authors

  • Iyer, AS||Witherden, FD||Chernyshenko, SI||Vincent, PE

publication date

  • September 2019