The motion of a two-dimensional incompressible inviscid and homogeneous fluid can be thought of in terms of the gradual evoluwhere u, , and P denote fluid velocity, density, and prestion of a continuous vorticity distribution, each scalar vortex element sure, respectively. Provided that no free surfaces are presinteracting with every other by an instantaneous action at a distance ent it is convenient to eliminate these primitive variables, law. It is of particular interest that this model can be expressed in introducing the vorticity and stream function ac-Hamiltonian form and that it shows many analogies with similar systems in plasma physics. In addition to the standard mesh tech-cording to niques, a computational description can be obtained if the continuous vorticity distribution is replaced by a finite set of point vortices ฯญ ูก ฯซ u, u ฯญ ูก ฯซ .
(3) interacting through a stream function which satisfies Poisson's equation. The point vortices move in a velocity field given on a
For a two-dimensional flow field we can consider ฯญ
Cartesian mesh such that there is a close resemblance to particle models used in plasma simulations. The point vortex model is pre-(0, 0, ) and ฯญ (0, 0, ) as scalars and Eqs. ( 1) and ( 2)
sented with a calculation on a test model and the sources of numerithen become cal errors are explained. Graphical results from several calculations are shown and it is concluded that the point vortex model is useful
and versatile for a variety of problems in hydrodynamics as well as in plasma physics. แฎ 1973 Academic Press
where for any two scalars A and B