Turbulence: from Complexity to Variety

Abstract

In this note we advocate the notion of variety as juxtaposed to the notion of complexity. Laminar flows are complex, turbulence is various. When the gradients reach a critical point, laminar flows are subjected to instabilities and transitions, sometime soft, sometime dramatic, and the final result is the variety. Turbulent flows in nature are fascinating, and loosely speaking we could say that a system is complex when differences are suffered, is various when diversities are enjoyed and exploited as opportunities.