This book provides an introduction to the theory of turbulence in fluids
based on the representation of the flow by means of its vorticity field.
It has long been understood that, at least in the case of incompressible
flow, the vorticity representation is natural and physically
transparent, yet the development of a theory of turbulence in this
representation has been slow. The pioneering work of Onsager and of
Joyce and Montgomery on the statistical mechanics of two-dimensional
vortex systems has only recently been put on a firm mathematical
footing, and the three-dimensional theory remains in parts speculative
and even controversial. The first three chapters of the book contain a
reasonably standard intro- duction to homogeneous turbulence (the
simplest case); a quick review of fluid mechanics is followed by a
summary of the appropriate Fourier theory (more detailed than is
customary in fluid mechanics) and by a summary of Kolmogorov's theory of
the inertial range, slanted so as to dovetail with later vortex-based
arguments. The possibility that the inertial spectrum is an equilibrium
spectrum is raised.