Balanced Vortex: Introduction


The purpose of this project is to study the balance of forces in a vortex using examples from rotating fluid experiments and atmospheric data of hurricane flow.

Flow patterns (left) in the radial inflow experiment and IR satellite image (right) of hurricane Katrina on August 29, 2005.

The experiment involves setting up a fluid vortex, measuring the resulting flow and interpreting measurements in terms of associated theory. The experiment exhibits a number of important principles of rotating fluid dynamics – conservation of angular momentum, geostrophic, gradient wind and cyclostrophic balance. It also provides an ideal context in which to introduce and discuss the Rossby number.

Atmospheric observations of a hurricane are used to identify analogous regions of geostrophic, gradient wind and cyclostrophic flow. The observed regimes are discussed in terms of the Rossby number.