In this paper we consider the time evolution of vortices simulated by
the method of contour dynamics. Special attention is being paid to the
Hamiltonian character of the governing equations and in particular to
the conservational properties of numerical time integration for them.
We assess symplectic and nonsymplectic schemes. For the former method
s, we give an implementation which is both efficient and yet effective
ly explicit. A number of numerical examples sustain the analysis and d
emonstrate the usefulness of the approach. (C) 1997 Academic Press.