shearing instability

Same as Helmholtz instability.

1. A complex hydrodynamic instability phenomenon exhibited by a stratified shear flow.
   A necessary condition for this type of instability is that the local Richardson number is somewhere less than one-quarter.
   Drazin, P. G., and W. H. Reid 1981. Hydrodynamic Stability. Cambridge University Press, . 325–333.