Reconnaissance data for a hurricane give a wind that is very nearly horizontal and…
PHYSICS · Multi-part · Fermi University Physics · Mathematical Methods for Physics · Fluids & Continuum Physics · Kinematics, conservation laws and ideal flow
Fluids and Continuum Physics, Ch Vorticity, circulation and vortex motion
Problem
Reconnaissance data for a hurricane give a wind that is very nearly horizontal and blowing anticlockwise round the eye (viewed from above, with z upward, so anticlockwise is positive). At a radius of 30km from the centre the wind speed is 45ms−1, and the flow may be taken as steady and axisymmetric, so that the wind at that radius is everywhere tangential and of that speed.
((a)) Estimate the circulation round the horizontal circle of radius 30km centred on the eye.
((b)) Hence estimate the average vertical component of vorticity, ωz, over the horizontal disc bounded by that circle.