Effects of particle sedimentation and rotation on axisymmetric gravity currents

The axisymmetric propagation of a relatively dense gravity current of a giv en initial volume over a horizontal boundary is considered when the intrudi ng fluid is a suspension of heavy particles and the ambient fluid is steadi ly rotating about a vertical axis. The investigation employs a shallow-wate r model of the motion. With the introduction of a strained temporal coordin ate, it is possible to derive asymptotic expressions for the evolution of t he radius and height of the current, the radial and temporal variation of t he horizontal velocity, the volume fraction of particles, and the angular v elocity. In this way it is possible to distinguish how the Coriolis force a nd the effects of particle sedimentation inhibit the radial spreading of th e flow. The analytical relationships arise directly from the shallow-water equations and thus improve upon previous simple expressions which are based on an a priori prescription of the shape for the current. The analytical r esults compare favorably with both numerical integration of the full system of equations and experimental data.(C) 2001 American Institute of Physics.