Three-dimensional evolution of large-scale vortices in supersonic flow

Abstract

The supersonic large-scale vortices generated by a streamwise vortex generator were investigated experimentally using the nanoparticle-based planar laser scattering method, with the emphasis on the entrainment and mixing characteristics in supersonic mixing layer. The spanwise coherent structures originated from the K-H instability grew up along with the vortex pairing process, which are able to exist in far field downstream of trailing edge. The large-scale streamwise vortex shed from the generator plays a major role in entraining the surrounding fluid from both sides of interface into mixing zone. Meanwhile, through the interaction with spanwise vortices, the streamwise vortex breaks up into the small-scale structures for molecular mixing. Moreover, the T-shaped structures and secondary K-H vortices are shown to be the usual topological structures in small-scale turbulence transport.

Spiral Spectrum of a Laguerre-Gaussian Beam Propagating in Anisotropic Turbulent Plasma

“…Instead, in the field of computational electromagnetics, more attention is paid to the electron density [18][19][20] or collision frequency [21,22] of this medium. Theories and experiments also show that the hypersonic plasma sheath has turbulent characteristics [23,24]. Therefore, similar to the atmospheric turbulence, it also follows the statistical average theory.…”

Fluid vortex mapping using the rotational Doppler effect

“…From an experimental point of view, vorticity is usually estimated from a number of velocity field measurements at 10 several points near the point of interest, which then allow computation of the velocity derivatives over space. This could be achieved through Laser Doppler Velocimetry, Particle Image Velocimetry, or Molecular Tagging Velocimetry, for example [5,6]. These methods then provide an indirect measurement of vorticity by reconstruction of the velocity field.…”