Vortex stretching in a homogeneous isotropic turbulence

15th Asian Congress of Fluid Mechanics

物理学;力学

Hirota, M.^1 ; Nishio, Y.^1 ; Izawa, S.^1 ; Fukunishi, Y.^1

Mechanical Systems and Design, Graduate School of Engineering, Tohoku University, 6-6-01 Aramaki-Aoba, Aoba-ku, Miyagi, Sendai

980-8579, Japan^1

关键词: Fourier;    Geometric relations;    Homogeneous isotropic turbulence;    Inertial subrange;    Vortex axis;    Vortex interactions;    Vortex stretching;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/822/1/012041/pdf
DOI  :  10.1088/1742-6596/822/1/012041

学科分类：力学，机械学

来源: IOP

【 摘 要 】

Stretching vortices whose sizes are in the inertial subrange of a homogeneous isotropic turbulence are picked up, and the geometric relations with the neighboring vortices whose scales are twice larger are studied. Hierarchical vortices are extracted using a Fourier band-pass filter, and each extracted vortex is reconstructed as a set of short cylindrical segments along the vortex axis to discuss the vortex interactions. As a result, it is shown that the directions of larger vortices near the segments of the fast stretching vortices tend to be orthogonal to the direction of the stretching segments, and the locations of the larger vortices that contribute most to the stretching of smaller vortex segments are likely to be found in the direction with the relative angle of 45° from the axes of the stretching vortex segments. And, the vortices with the second highest contributions tend to be in the directions 45° from the stretching segments' axes and orthogonal to the directions of the highest contributing vortices.