Three‐dimensional optimal perturbations in viscous shear flow

摘要: Transition to turbulence in plane channel flow occurs even for conditions under which modes of the linearized dynamical system associated with are stable. In this paper an attempt is made understand phenomena by finding linear three‐dimensional perturbations that gain most energy a given time period. A complete set perturbations, ordered growth, found using variational methods. The optimal not modal form, and those grow resemble streamwise vortices, divert mean into streaks velocity enable perturbation as much three orders magnitude. It suggested excitation these facilitates transition from laminar turbulent flow. method used find shear also allows construction tight bounds on growth rate determination regions absolute stability no possible.