Conservation properties of smoothed particle hydrodynamics applied to the shallow water equation

Kelvin's circulation theorem and its implications for potential vorticity (PV) conservation are among the most fundamental concepts in ideal fluid dynamics. In this note, we discuss the numerical treatment of these concepts with the Smoothed Particle Hydrodynamics (SPH) and related methods. We show that SPH satisfies an exact circulation theorem in an interpolated velocity field, and that, when appropriately interpreted, this leads to statements of conservation of PV and generalized enstrophies. We also indicate some limitations where the analogy with ideal fluid dynamics breaks down.