This paper describes features in the structure of a laminar vortex ring ejected vertically from an elevated pipe into a uniform horizontal cross flow. Measurements are obtained by particleimage velocimetry (PIV) and flow-visualisation images are obtained by planar-laser-induced fluorescence (PLIF). Cross flow produces a shear layer over the open end of the elevated pipe. As a vortex ring is eje...

The interaction of a vortex pair with a premixed flame serves as an important prototype for premixed turbulent combustion. In this study, we investigate the interaction of a counter-rotating vortex pair with an initially flat premixed methane flame. We compare computational solutions obtained using a timedependent, two-dimensional adaptive low Mach number combustion algorithm that incorporates ...

We present results from a combined experimental and numerical investigation of the flow around rectangular NACA 0012 wing, whose tip geometry is modified by addition perpendicular fin. The purpose this modification to generate system two closely-spaced concentrated vortices, instead familiar single trailing vortex. Experiments were carried out in water tunnel, where velocity measurements made n...

A vortex molecule is predicted in rotating two-component Bose-Einstein condensates whose internal hyperfine states are coupled coherently by an external field. A vortex in one component and one in the other are connected by a domain wall of the relative phase, constituting a "vortex molecule," which features a nonaxisymmetric (pseudo)spin texture with a pair of merons. The binding mechanism of ...

The wake of an isolated, rotating wheel a geometry typical those used in open-wheel motorsport, is investigated. CFD validated by comparing the data gathered from this method with PIV wind tunnel experiments, where analysis showed good agreement between two methods. A comparison mean and instantaneous flow-fields obtained shows significant differences topology. time-averaged illustration flow i...

Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. 461 Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jet...

We consider the spatio-temporal development of the long-wave and shortwave instabilities in a pair of counter-rotating vortices in the presence of a uniform axial advection velocity. The stability properties depend upon the aspect ratio a=b of the vortex pair, where a is the core radius of the vortices and b their separation, and upon W 0 =U 0 the ratio between the self-induced velocity of the ...

It is shown that optical vortex beams can be generated from a non-vortex fundamental beam by an optical frequency conversion process taking place within a twisted nonlinear photonic crystal. This is done without any first-order (linear) refractive optics. Through such a proposed structure, all-optical switching of vortices with different helicities is made possible, as well as the simultaneous ...

It is of great theoretical interest to investigate the interaction between ames and vortices as a model problem to study turbulent combustion because a eld of turbulence can be considered as an ensemble of vortices of various length and time scales. Interaction between ames and vortices governs the rate of combustion and results in di erent types of instabilites. The goal of this study is to un...