Unstable jet, with perturbation (16.6 MB)

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A purely zonal (west to east) jet stream is a steady state solution of the barotropic vorticity equation, but it is an unstable equilibrium, meaning that small perturbations in the jet will grow in time.  Here, a wavenumber 12 perturbation is added to the jet, and the instability triggers vortex roll-up along the jet axis.  

© Peter Bosler 2013