The three archetypes of relaminarisation

Three mechanisms for the reversion of turbulent flow to a laminar state are examined. The first involves the dissipation of turbulence energy through the action of a molecular transport property such as viscosity or conductivity, with the Reynolds number the governing parameter. The second involves the dissipation of turbulence energy by work done against an external agency such as buoyancy force or flow curvature, with the Richardson number the governing parameter. The third is exemplified by a turbulent boundary layer subjected to severe acceleration and involves the predomination of pressure forces over slowly responding Reynolds stresses accompanied by the generation of a new laminar boundary layer stabilized by the acceleration.