Abstract
Patterns of vortex ripples form when a sand bed is subjected to an oscillatory fluid flow. Here we describe experiments on the response of regular vortex ripple patterns to sudden changes of the driving amplitude or frequency . A sufficient decrease of leads to a “freezing” of the pattern, while a sufficient increase of leads to a supercritical secondary “pearling” instability. Sufficient changes in the amplitude lead to subcritical secondary “doubling” and “bulging” instabilities. Our findings are summarized in a “stability balloon” for vortex ripple pattern formation.
- Received 22 June 2001
DOI:https://doi.org/10.1103/PhysRevLett.87.204301
©2001 American Physical Society