Lectures on Fluid Dynamics

In these lectures, most of them given at the University of Montreal while he held the Aisenstadt Chair, Roman Jackiw provides a view of fluid dynamics from an entirely novel perspective. He begins by explaining the motivation and reviewing the classical theory, but in a manner different from textbook discussions. Among other topics, he discusses conservation laws and Euler equations, and a method for finding their canonical structure; C. Eckart's Lagrangian and a relativistic generalization for vortex-free motion; nonvanishing vorticity and the Clebsch parameterization for the velocity vector. Jackiw then discusses some specific models for nonrelativistic and relativistic fluid mechanics with more than one spatial dimension, including the Chaplygin gas (whose negative pressure is inversely proportional to density), and the scalar Born-Infeld model. He shows how both the Chaplygin gas and the Born-Infeld model devolve from the parameterization-invariant Nambu-Goto action. As in particle physics, Jackiw shows, fluid mechanics enhanced by supersymmetry, non-Abelian degrees of freedon, and non commuting coordinates. Jackiw discusses the need for a non-Abelian fluid mechanics, and proposes a Lagrangian, which involves a non-Abelian auxiliary field, whose Chern-Simons density should be a total derivative. The generalization to magnetohydrodynamics, which results from including a dynamical non-Abelian guage filed, reduces in the Abelian limit to conventional magnetohydrodynamics. For one-dimensional cases, the models mentioned above are completely integrable, and Jackiw gives the general solution of the Chaplygin gas and the Born-Infeld model on a line, as well as a general solution of the Nambu-Goto theory for a 1-brane (string) in two spatial dimensions. Jackiw discusses the need for a non-Abelian fluid mechanics and proposes a Lagrangian, which involves a non-Abelian auxiliary field whose Chern-Simons density should be a total derivative. The generalization to magnetohydrodynamics, which results from including a dynamical non-Abelian gauge field, reduces in the Abelian limit to conventional magnetohydrodynamics.