Energy transfer in turbulence under rotation

Michele Buzzicotti, H. Aluie, Luca Biferale, Moritz Linkmann

Research output: Contribution to journalArticlepeer-review

Abstract

t is known that rapidly rotating turbulent flows are characterized by the emergence of simul-taneous upscale and downscale energy transfer. Indeed, both numerics and experiments show theformation of large-scale anisotropic vortices together with the development of small-scale dissipa-tive structures. However the organization of interactions leading to this complex dynamics remainsunclear. Two different mechanisms are known to be able to transfer energy upscale in a turbulentflow. The first is characterized by two-dimensional interactions among triads lying on the two-dimensional, three-component (2D3C)/slow manifold, namely on the Fourier plane perpendicular tothe rotation axis. The second mechanism is three-dimensional and consists of interactions betweentriads with the same sign of helicity (homochiral). Here, we present a detailed numerical study ofrotating flows using a suite of high Reynolds number direct numerical simulations (DNS) withindifferent parameter regimes to analyze both upscale and downscale cascade ranges. We find thatthe upscale cascade at wave numbers close to the forcing scale is generated by increasingly dominanthomochiral interactions which couple the three-dimensional bulk and the 2D3C plane. This couplingproduces an accumulation of energy in the 2D3C plane, which then transfers energy to smaller wavenumbers thanks to the two-dimensional mechanism. In the forward cascade range, we find thatthe energy transfer is dominated by heterochiral triads and is dominated primarily by interactionwithin the fast manifold wherekz6= 0. We further analyze the energy transfer in different regionsin the real-space domain. In particular, we distinguish high-strain from high-vorticity regions andwe uncover that while the mean transfer is produced inside regions of strain, the rare but extremeevents of energy transfer occur primarily inside the large-scale column vortices
Original languageEnglish
Article number034802
Number of pages20
JournalPhysical Review Fluids
Volume3
Issue number3
DOIs
Publication statusPublished - 21 Mar 2018

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