Coherent structures in wall-turbulence
Coherent structures—loosely defined as regions of concentrated velocity, vorticity, characteristic and flow-specific organization, recurrence, appreciable lifetime, and scale—have been the foremost object of scientific curiosity and dispute in turbulence research for decades.
We plan to examine the coherent structures with time-resolved data from direct numerical simulation of high-Reynolds-number turbulent flows. Access to spatiotemporally resolved data allows us to explore new frontiers in coherent-structure identification and study the life-cycle of the coherent structures as they evolve in time.
H. J. Bae & M. Lee "Life-cycle of streaks in the buffer layer of wall-bounded turbulence", Physical Review Fluids, Physical Review Fluids 6, 064603, 2021 (selected editor's suggestion).
Self-sustaining process of wall-bounded turbulence
In the vicinity of the wall, the flow is found to be highly organized and can be comprehended as a collection of recurrent patterns also known as the self-sustaining process. This highly nonlinear process of turbulence regeneration is still not fully understood.
Our goal is to study the self-sustaining process with novel methods to uncover the mechanism of turbulence generation in the vicinity of the wall.
H. J. Bae, A. Lozano-Durán & B. J. McKeon, "Nonlinear mechanism of the self-sustaining process in the buffer and logarithmic layer of wall-bounded flows", Journal of Fluid Mechanics, 914, A3, 2021.
A. Lozano-Durán, H. J. Bae & M. P. Encinar, "Causality of energy-containing eddies in wall turbulence", Journal of Fluid Mechanics, 882, A2, 2020.