Evolution of flow structures and the dynamics of helicity under the effects of Coriolis force in inhomogeneous rotating turbulence
Phys. Rev. Fluids 10, 074802 – Published 14 July, 2025
DOI: https://doi.org/10.1103/kqwb-wh3v
Abstract
Inhomogeneous rotating turbulence is ubiquitous in nature and engineering. However, people are still unfamiliar with the dual cascade of energy and helicity in inhomogeneous rotating turbulence. In this paper, our aim is to study the effects of the inhomogeneous Coriolis force on the evolution of flow structures and the dynamics of helicity. On this issue, we performed direct numerical simulation (DNS) on several cases of the simplified inhomogeneous rotational turbulence with cosine distribution of angular velocity. The DNS results demonstrate the spectra of energy and helicity and the interscale transfer of energy and helicity. The Biot-Savart law exhibits the influences of the Coriolis force. In conclusion, the flow field under the effects of the inhomogeneous Coriolis force can be categorized into three regions, namely, the helicity-dominated region, the dual cascade region, and the rotation-dominated region. The energy cascades downscale through the average transfer effect, while the helicity cascades downscale relying on extreme events. In addition, the decomposition of the Coriolis force shows that the Coriolis force accounts for the formation of dumbbell-shaped columnar structures and the generation of helicity.
