Vortex filament
= Vortex filament
A <vortex filament> is the ideal thin-core limit of a <vortex tube>, concentrating a finite <circulation (physics)> on a curve. In an unbounded incompressible <fluid> with <velocity> tending to zero at infinity, its induced <velocity field> follows the <vorticity> version of the <Biot-Savart law>. The ideal field is singular on the filament; finite-core models are needed there. A closed circular filament is a thin <vortex ring>.