High resolution DPIV measurements are made of a vortex ring formed by a piston/cylinder mechanism ~Reynolds number 3700 and 7500!. A complex ring structure is identified. The stopping condition of the piston leads to vortical fluid collecting near the forward stagnation point of the ring. In addition, the roll-up of the core produces a vorticity distribution that departs from a simple Gaussian ...

We demonstrate the formation of hierarchical structures in two-dimensional systems with multiple length scales in the inter-particle interaction. These include states such as clusters of clusters, concentric rings, clusters inside a ring, and stripes in a cluster. We propose to realize such systems in vortex matter (where a vortex is mapped onto a particle with multi-scale interactions) in laye...

In an investigation on vortex rings suggested to me by Prof. Tomaschek, we succeeded in observing a novel 18 phenomenon, namely the appearance of waves on the core of the vortex ring and unstable regions within the 19 rings. The success was mainly attributed to novel coloring method we applied. The present paper presents 20 a thorough description of the observed phenomena, specifically includin...

The dynamics of pulsed jetting in squids throughout ontogeny is not well understood, especially with regard to the development of vortex rings, which are common features of mechanically generated jet pulses (also known as starting jets). Studies of mechanically generated starting jets have revealed a limiting principle for vortex ring formation characterized in terms of a ;formation number' (F)...

We reveal the existence of dynamically stable composite topological solitons in Bessel photonic lattices imprinted in focusing Kerr-type nonlinear media. The new stable composite solitons are made of a vortex-ring with unit topological charge incoherently coupled to a fundamental soliton. The stabilization of the otherwise highly azimuthally unstable vortex-rings is provided under suitable cond...

We report the results of a theoretical investigation of the stability of a toroidal vortex bound by an interface. Two distinct instability mechanisms are identified that rely on, respectively, surface tension and fluid inertia, either of which may prompt the transformation from a circular to a polygonal torus. Our results are discussed in the context of three experiments, a toroidal vortex ring...

Stable ring-profile vortex solitons, featuring a bright shape, appear to be very rare in nature. However, here we show that they exist and can be made dynamically stable in defocusing cubic nonlinear media with an imprinted Bessel optical lattice. We find the families of vortex solitons and reveal their salient properties, including the conditions required for their stability. We show that the ...

Submitted for the MAR10 Meeting of The American Physical Society Vortex ring refraction at large Froude numbers1 KERRY KUEHN, MATTHEW MOELLER, MICHAEL SCHULZ, DANIEL SANFELIPPO, Wisconsin Lutheran College — We have experimentally studied the impact of a planar axisymmetric vortex ring, incident at an oblique angle, upon a sharp gravity-induced interface separating two fluids of differing densit...

New results are reported on the propagation of a vortex ring through immiscible fluid interfaces in the limit of high Weber number in microgravity and in I-G. The main objective of the tests is to detennine the effect of density and viscosity ratios on the dynamics of the interaction. It is shown that density ratio plays a controlling role in determining the outcome of the interaction. For smal...