Flow structures, nonlinear inertial waves and energy transfer in rotating spheres

Li，Tianyi1,2; Wan，Minping1,3; Chen，Shiyi1,2,3

2021

10.1016/j.taml.2021.100312

Theoretical and Applied Mechanics Letters   影响因子和分区

2095-0349

2095-0349

We investigate flow structures, nonlinear inertial waves and energy transfer in a rotating fluid sphere, using a Galerkin spectral method based on helical-wave decomposition (HWD). Numerical simulations of flows in a sphere are performed with different system rotation rates, where a large-scale forcing is employed. For the case without system rotation, the intense vortex structures are tube-like. When a weak rotation is introduced, small-scale structures are reduced and vortex tubes tend to align with the rotation axis. As the rotation rate increases, a large-scale anticyclonic vortex structure is formed near the rotation axis. The structure is shown to be led by certain geostrophic modes. When the rotation rate further increases, a cyclone and an anticyclone emerge from the top and bottom of the boundary, respectively, where two quasi-geostrophic equatorially symmetric inertial waves dominate the flow. Based on HWD, effects of spherical confinement on rotating turbulence are systematically studied. It is found that the forward cascade becomes weaker as the rotation increases. When the rotation rate becomes larger than some critical value, dual energy cascades emerge, with an inverse cascade at large scales and a forward cascade at small scales. Finally, the flow behavior near the boundary is studied, where the average boundary layer thickness gets smaller when system rotation increases. The flow behavior in the boundary layer is closely related to the interior flow structures, which create significant mass flux between the boundary layer and the interior fluid through Ekman pumping.

Helical-wave deomposition Inertial wave Rotating turbulence Spherical confinement

ESCI

英语

第一 ; 通讯

National Natural Science Foundation of China (NSFC) Basic Science Center Program[11988102] ; NSFC[91752201] ; Department of Science and Technology of Guangdong Province[2019B21203001] ; Shenzhen Science and Technology Innovation Commission[KQTD20180411143441009] ; Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)[GML2019ZD0103]

Mechanics

Mechanics

WOS:000748986400010

ELSEVIER

2-s2.0-85121720904

Scopus

1.Guangdong Provincial Key Laboratory of Turbulence Research and Applications,Department of Mechanics and Aerospace Engineering,Southern University of Science and Technology,Shenzhen,518055,China
2.State Key Laboratory for Turbulence and Complex Systems,College of Engineering,Peking University,Beijing,100871,China
3.Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou),Guangdong,No. 1119, Haibin Rd., Nansha District, Guangzhou,511458,China

Li，Tianyi,Wan，Minping,Chen，Shiyi. Flow structures, nonlinear inertial waves and energy transfer in rotating spheres[J]. Theoretical and Applied Mechanics Letters,2021,11(6).

Li，Tianyi,Wan，Minping,&Chen，Shiyi.(2021).Flow structures, nonlinear inertial waves and energy transfer in rotating spheres.Theoretical and Applied Mechanics Letters,11(6).

Li，Tianyi,et al."Flow structures, nonlinear inertial waves and energy transfer in rotating spheres".Theoretical and Applied Mechanics Letters 11.6(2021).