2006/05/19 by Liang Sun, Sun Liang
Engineering · Physics and Astronomy · #Fluid Dynamics and Turbulent Flows #Fluid Dynamics and Vibration Analysis #Fluid dynamics and aerodynamics studies #physics.ao-ph #physics.flu-dyn
paper · pdf · doi:10.1088/0256-307x/25/4/049
published as 2008 Chinese Phys. Lett. 25 1343-1346 · Revtex4, 4 pages, 1 figure, extends the second part of physics/0512208
arxiv created 2006/05/19 · openalex publication_date 2008/04/01 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/04
The essence of shear instability is reviewed both mathematically and physically, which extends the instability theory of a sheet vortex from the viewpoint of vortex dynamics. For this, the Kelvin–Arnol'd theorem is retrieved in linear context, i.e., the stable flow minimizes the kinetic energy associated with vorticity. Then the mechanism of shear instability is explored by combining the mechanisms of both Kelvin–Helmholtz instability (K-H instability) and resonance of waves. The waves, which have the same phase speed with the concentrated vortex, have interactions with the vortex to trigger the instability. The physical explanation of shear instability is also sketched by extending Batchelor's theory. These results should lead to a more comprehensive understanding on shear instabilities.