Spatial Evolution of Disturbances in Plane Poiseuille Flow

Abstract

The spatial evolution of disturbances in plane Poiseuille flow is considered. For disturbances governed by the linearized equations potential for significant transient growth of the amplitude has been found. The maximum amplification occurs for disturbances with zero or low frequencies. Spatial numerical simulations of the complete transition scenario involving a pair of oblique waves have also been conducted. A modal decomposition indicates that non-linear excitation of the transient growth is responsible for the rapid emergence of low-frequency structures. Physically, this results in streaky flow structures, as seen from the results of a numerical amplitude expansion. Thus, this spatial transition scenario has been found to be similar to the corresponding temporal one (Schmid & Henningson, 1992).KeywordsSpatial EvolutionTransient GrowthOblique WaveTransition ScenarioMaximum AmplificationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.