“classical” Vortex Nucleation in Superflow through Small Orifices
نویسندگان
چکیده
We report on numerical solutions of the Gross-Pitaevskii equation for two-dimensional flow of a superfluid condensate through a small orifice. Above a critical velocity of about 30% of the speed of sound, cavitation occurs in the throat of the orifice. The cavitating bubbles form the cores of singly quantized vortices which detach from the boundary and are convected downstream.
منابع مشابه
Scaling laws for vortical nucleation solutions in a model of superflow
The bifurcation diagram corresponding to stationary solutions of the nonlinear Schrödinger equation describing a superflow around a disc is numerically computed using continuation techniques. When the Mach number is varied, it is found that the stable and unstable (nucleation) branches are connected through a primary saddle-node and a secondary pitchfork bifurcation. Computations are carried ou...
متن کاملVortex shedding in a model of superflow
The present article represents part of the PhD. dissertation by C. Josserand1. We discuss the nucleation of quantized vortices in the nonlinear Schrödinger equation (NLS) for a flow around a disk in two spatial dimensions. It appears that the vortices are nucleated when the flow becomes locally (at the edge of the disk) supersonic. A detailed study of the phase equation for the complex field ψ ...
متن کاملMicroscopic analysis of the nondissipative force on a line vortex in a superconductor: Berry's phase, momentum flow, and the Magnus force.
A microscopic analysis of the non-dissipative force Fnd acting on a line vortex in a type-II superconductor at T = 0 is given. We first examine the Berry phase induced in the true superconducting ground state by movement of the vortex and show how this phase introduces a Wess-Zumino term in the hydrodynamic action Shyd of the superconducting condensate. Appropriate variation of Shyd gives Fnd a...
متن کاملSoliton trains and vortex streets as a form of Cerenkov radiation in trapped Bose-Einstein condensates
We numerically study the nucleation of gray solitons and vortex–antivortex pairs created by a moving impurity in, respectively, 1D and 2D Bose–Einstein condensates (BECs) confined by a parabolic potential. The simulations emulate the motion of a localized laser-beam spot through the trapped condensate. Our results for the 1D case indicate that, due to the inhomogeneity of the BEC density, the c...
متن کاملIntrinsic and Extrinsic Vortex Nucleation Mechanisms in the Ow
We propose very general vortex nucleation mechanismss1] analogous to a hydrodynamic instability and calculate associated critical velocity in agreement with experiments. The creation of vortices via extrinsic mechanism is driven by a formation of the surface vorticity sheet created by the ow, which reaches a critical size. Such a sheet screens an attraction of a half-vortex ring to the wall, th...
متن کامل