Major research outcome
- Dr. Yedam Lee and Professor Sang Lee Unveil Tail-like Vortical Structures in Extreme Turbulent Kinetic Energy Dissipation Events
- 관리자 |
- 2026-05-10 11:42:30|
- 49
- 2026-05-10 11:42:30|
Wall-bounded turbulence represents a canonical flow system in which energy transfer and dissipation are strongly coupled through nonlinear interactions. In particular, extreme turbulent kinetic energy (TKE) dissipation events play a dominant role in overall turbulence dissipation, yet their structural origin and underlying physical mechanisms remain insufficiently understood. Under the supervision of Prof. Sang Lee at the Department of Aerospace Engineering, KAIST, Dr. Yedam Lee conducted direct numerical simulations (DNS) of turbulent channel flows at friction Reynolds numbers Reτ = 180, 395, and 640. To extract extreme dissipation events without bias, a novel analysis framework combining connected-component labeling and spatio-temporal tracking was developed. In addition, a Rortex-based vortex identification method—capable of suppressing shear contamination and providing directional information—was employed to precisely characterize the vortical structures surrounding extreme events.
The results revealed, for the first time, a previously unidentified tail-like vortical structure that consistently accompanies extreme TKE dissipation events. This structure is connected to quasi-streamwise vortices but exhibits a distinct inclination in the opposite direction, forming a unique geometric configuration. It is strongly associated with sweep events characterized by positive streamwise velocity fluctuations and negative wall-normal velocity fluctuations. Furthermore, the structure shows a dominant negative spanwise rotational component, providing new physical insights into turbulence intermittency and extending existing models of turbulent structures.
This study reveals the structural origin of extreme energy dissipation phenomena in turbulence, offering a new physical interpretation framework beyond conventional mean-based turbulence models. In particular, the identification of the tail-like structure suggests a need to revisit the classical understanding of near-wall turbulence. The findings are expected to serve as a foundational basis for high-fidelity turbulence modeling, improved LES subgrid-scale models, and physics-informed AI approaches for turbulent flow prediction.
This work was published online in March 2026 in Physics of Fluids, a top-tier Q1 international journal in fluid mechanics.
https://doi.org/10.1063/5.0320686
The results revealed, for the first time, a previously unidentified tail-like vortical structure that consistently accompanies extreme TKE dissipation events. This structure is connected to quasi-streamwise vortices but exhibits a distinct inclination in the opposite direction, forming a unique geometric configuration. It is strongly associated with sweep events characterized by positive streamwise velocity fluctuations and negative wall-normal velocity fluctuations. Furthermore, the structure shows a dominant negative spanwise rotational component, providing new physical insights into turbulence intermittency and extending existing models of turbulent structures.
This study reveals the structural origin of extreme energy dissipation phenomena in turbulence, offering a new physical interpretation framework beyond conventional mean-based turbulence models. In particular, the identification of the tail-like structure suggests a need to revisit the classical understanding of near-wall turbulence. The findings are expected to serve as a foundational basis for high-fidelity turbulence modeling, improved LES subgrid-scale models, and physics-informed AI approaches for turbulent flow prediction.
This work was published online in March 2026 in Physics of Fluids, a top-tier Q1 international journal in fluid mechanics.
https://doi.org/10.1063/5.0320686
| Attach File |
|---|