Vortex sheet dynamics and turbulence

Abstract

The nonlinear evolution of a vortex sheet driven by the Kelvin--Helmholtz instability is characterized by the formation of a spiral possessing complex stretching and intensity patterns. We show that the power energy spectrum of a single two-dimensional vortex sheet tends to the usual fluid turbulent spectrum, with an exponent of -3. Using numerical simulations and asymptotic methods, we demonstrate the relation between this power law and the singularities in the geometry and vorticity distribution of the sheet.