Recently, the existence of so-called granular bubbles and droplets has been demonstrated experimentally. Granular are clusters particles that respectively rise sink if submerged in an aerated vibrated bed another material different size and/or density. However, currently there is no model explains coherent motion these predicts transition between a rising sinking motion. Here, we propose analyt...

Closure relations are presented for the lift coe.cient for ordered arrays of 2-D and 3-D bubbles at various bubble volume fractions. These were determined via lattice Boltzmann simulations of bubble rise in periodic boxes, where the bubbles were also subjected to shear. The single-bubble lift coe.cient, determined by low-shear computational experiments, varies in a systematic manner with the as...

Active galactic nuclei inject large amounts of energy into their host galaxies and surrounding environment, shaping properties evolution1,2. In particular, active-galactic-nuclei jets inflate cosmic-ray lobes, which can rise buoyantly as light ‘bubbles’ in the medium3, displacing heating encountered thermal gas thus halting its spontaneous cooling. These bubbles have been identified a wide rang...

Most cool core clusters of galaxies possess active galactic nuclei (AGN) in their centers. These AGN inflate buoyant bubbles containing non-thermal radio emitting particles. If such bubbles efficiently confine cosmic rays (CR) then this could explain “radio ghosts” seen far from cluster centers. We simulate the diffusion of cosmic rays from buoyant bubbles inflated by AGN. Our simulations inclu...

It has been suggested that rising bubbles in dense fluids resemble an inverted dripping faucet and that they undergo analogous period-doubling bifurcations to chaos. We present experimental results demonstrating that this analogy is weak because the dominant source of instability in the bubble train is inherently different mutual interactions between spatially separated bubbles as opposed to no...

A granular instability driven by gravity is studied experimentally and numerically. The instability arises as grainsfall in a closed Hele-Shaw cell where a layer of dense granular material is positioned above a layer of air. The initially flatfront defined by the grains subsequently develops into a pattern of falling granular fingers separated by rising bubbles of air. Atransient co...

A granular instability driven by gravity is studied experimentally and numerically. The instability arises as grains fall in a closed Hele-Shaw cell where a layer of dense granular material is positioned above a layer of air. The initially flat front defined by the grains subsequently develops into a pattern of falling granular fingers separated by rising bubbles of air. A transient coarsening ...

Andreas Hanke Department of Physics and Astronomy, University of Texas, 80 Fort Brown, Brownsville Abstract While the Watson-Crick double-strand is the thermodynamically stable state of DNA in a wide range of temperature and salt conditions even at physiological conditions local denaturation bubbles may open up spontaneously due to thermal activation. By rising the ambient temperature, titratio...

The problem of a plane bubble rising in a 2-D tube is revisited using Birkhoff’s (1957) formulation. The equations in this formulation have a one parameter (Froude number F ) family of solutions which are divided into three regimes characterized by distinct topologies at the apex. These equations are solved numerically using a conventional series representation method and Newton’s iterations. T...