For thin films of superfluid adsorbed on a disordered substrate, we derive within a mean field (Hartree) description of the condensate the equation of motion for a vortex in the presence of a random potential. The compressible nature of the condensate leads to an effective pinning potential experienced by the vortex which is nonlocal, with a long range tail that smoothes out the random potentia...

Atmospheric turbulence has significant influences on both the trajectories and strengths of wake vortices. In this paper, a quasi-wavelet method is used to generate a random atmospheric turbulence field based on the von Kármán spectrum, in which atmospheric turbulence is represented by groups of random eddies. An inviscid wake vortex system, out-of-ground effect or in-ground effect, is immersed...

We study the general phenomenon of randomorganization using a vortex system.When a periodic shearwith a small shear amplitude dinp is applied tomany-particle (vortex) assemblies with a random distribution, the particles (vortices) gradually self-organize to avoid future collisions and transform into an organized configuration. This is detected from the time-evolution of the voltageV t ( ) (aver...

As a simplified model of randomly pinned vortex lattices or charge-density waves, we study the random-field XY model on square (d = 2) and simple cubic (d = 3) lattices. We verify in Monte Carlo simulations, that the average spacing between topological defects (vortices) diverges more strongly than the Imry-Ma pinning length as the random field strength, H, is reduced. We suggest that for d = 3...

We study the superfluid-insulator transition of a particle-hole symmetric system of long-range interacting bosons in a time-dependent random potential in two dimensions, using the momentum-shell renormalization-group method. We find a new stable fixed point with non-zero values of the parameters representing the shortand long-range interactions and disorder when the interaction is asymptoticall...

A vortex boundary element method is developed for the grid-free simulation of time-dependent , incompressible, viscous ow in three-dimensional conngurations. The numerical scheme is based on a combination of the Lagrangian vortex method to capture the convection and stretch of the vortical eld, the random walk method to describe the diiusion process, and the boundary element method to impose th...