Excitation of Nonlinear Equilibria in Laboratory Shear Flows
This work shows that transient growth of properly configured small amplitude initial perturbations leads to formation of finite amplitude nonlinear equilibria in shear flow. It demonstrates a trajectory in phase space leading from linear perturbations to nonlinear solutions.
Butler K. M., and B. F. Farrell 1994: Nonlinear equilibration of 2-D optimal perturbations in viscous shear flow. Phys. Fluids 6 A 2011-2020 pdf