Simulations of steady and oscillating flow in diffusers

In this thesis diffuser performance will be simulated with computational fluid dynamics, which will be done with the program Ansys Fluent. The expanding geometry creates an adverse pressure gradient and under certain conditions there will also be separation.<br/><br/>At first a relative simple simulation will be done of a one-directional...

Turbulence Transition in Shear Flows: Chaos in High-Dimensional Spaces

The study of the transition to turbulence in parallel shear flows without linear instability of the laminar profile has profited immensely from the application of dynamical systems ideas. Studies of the transition in plane Couette flow and pipe flow, in particular, have shown that the transition is connected with the appearance of 3-d coherent...

Localized turbulence in pipe flow

In this thesis the transition to turbulence in pipe flow is investigated. At low Reynolds numbers, the flow returns to the laminar state spontaneously. At high Reynolds number a small perturbation causes the flow to suddenly become turbulent. In the intermediate regime localized turbulence is observed. This regime is investigated using...