MIDIT OFD CATS Modelling, Nonlinear Dynamics Optics and Fluid Dynamics Chaos and Turbulence Studies and Irreversible Thermodynamics Risø National Laboratory Niels Bohr Institute and Technical University of Denmark Building 128 Department of Chemistry Building 321 P.O. Box 49 University of Copenhagen DK-2800 Lyngby DK-4000 Roskilde DK-2100 Copenhagen Ø Denmark Denmark Denmark
by Viktor P. Ruban
Landau Institute for Theoretical Physics
Wednesday November 29, 2000, 10.00 h
at OFD's Meeting room, Bld. 130,
Risø National Laboratory
Abstract: Starting from the Lagrangian formalism for an ideal compressible fluid, a variational principle for dynamics of frozen-in vortex lines is derived in the limit of slow flows, when deviations of the fluid density from an equilibrium state may be neglected because a velocity of vortex structure motion is small in comparison with the sound speed. Particularly, in spatially homogeneous systems, this limit corresponds to the approximation of an incompressible fluid. As examples how this method can be applied, the dynamics of a single thin vortex filament is considered, and also dynamics of two symmetric anti-parallel filaments. Advantages of the method are discussed.