My major research theme is geophysical fluid dynamics, including rotating stratified flows, rotating hydraulics, geophysical vortices (e.g. modons, beta-plane vortices) and topographic effects on geophysical flows. Collaborative work with Ted Johnson has lead to the development of numerical methods capable of computing vortex motion in complex domains e.g. barriers with gaps, multiple islands. With PhD student Rhodri Nelson these are being extended to cylindrical and spherical surfaces. More recently I have become interested in the use of complex variable methods to construct explicit solution to 2D free-boundary problems with non-zero vorticity. A variety of novel exact solutions having both geophysical and industrial applications have been found.