On Constructing the Minimal Seed of Turbulence: Nonlinear Transient Growth
arXiv:1009.0628
Abstract
Linear transient growth analysis is commonly used to suggest the structure of disturbances which are particularly efficient in triggering transition to turbulence in shear flows. We demonstrate that the addition of nonlinearity to the analysis can substantially change the prediction made in pipe flow from simple 2 dimensional streamwise rolls to a spanwise and cross-stream localised 3 dimensional state. This new nonlinear optimal is demonstrably more efficient in triggering turbulence than the linear optimal indicating that there are better ways to design perturbations to achieve transition.
4 pages, 5 figures. Substantially rewritten version of previous paper `Transient Growth in Shear Flows: Linearity vs Nonlinearity'. Now accepted to PRL