Spectral condensation in laboratory two-dimensional turbulence

Abstract

Due to the inverse energy cascade, when the energy dissipation length scale in two-dimensional turbulence is larger than the domain size, energy is expected to condense into the lowest allowed mode. Thus, the appearance of large-scale structures is often taken as a proxy for spectral condensation, particularly in laboratory realizations of two-dimensional turbulence. We show that large-scale flows alone, however, are not robust indicators of spectral condensation, because small domains may both weaken the inverse cascade and introduce new dissipation mechanisms.