2023/10/05 by Zhang, Linsen, Tao, Jianjun
#FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn)
paper · doi:10.48550/arxiv.2310.03238
Isolated turbulent bands observed in transitional channel flows have downstream heads and inclined bulks at a characteristic angle. In the large-scale mean flow, a ν-shape vortex found at the head elongates into the bulk part, forming a pair of counter-rotating vortex tube structures. It is revealed numerically and theoretically that the head and the bulk convection velocities reflect the obliquely forward and the backward self-induced velocities of the ν-shape vortex and the vortex tube pair, respectively, and the difference between these convection velocities provides a restoring angular momentum to retain the characteristic inclination angle through a self-adjustment process.