Evolution of finite amplitude Kelvin-Helmholtz billows in two spatial dimensions.

Abstract

A two-dimensional numerical model is used to calculate the nonlinear evolution of Kelvin-Helmholtz (KH) billows for various Reynolds numbers in the range where the turbulent collapse of the waves is expected. The onset of disordered motions is not observed in these numerical experiments, presumably because the transition requires the third spatial degree of freedom. Although we have shown elsehwere that these two-dimensional KH wave states are unstable with respect to three-dimensional perturbations, the spanwise coherent large-scale structure is observed to persist in presence of the small-scale fluctuations. -from Authors