Sökning: "Laminar-turbulent transition"
Visar resultat 1 - 5 av 36 avhandlingar innehållade orden Laminar-turbulent transition.
1. Optimal Control of Boundary Layer Transition
Sammanfattning : .... LÄS MER
2. Transition to turbulence in the asymptotic suction boundary layer
Sammanfattning : The focus of this thesis is on the numerical study of subcritical transition to turbulence in the asymptotic suction boundary layer (ASBL). Applying constant homogeneous suction prevents the spatial growth of the boundary layer, granting access to the asymptotic dynamics. LÄS MER
3. Stability and transition on wind turbine blades
Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER
4. Receptivity of Boundary-Layer Flows over Flat and Curved Walls
Sammanfattning : Direct numerical simulations of the receptivity and instability of boundary layers on flat and curved surfaces are herein reported. Various flow models are considered with the aim to capture aspects of flows over straight and swept wings such as wall curvature, pressure variations, leading-edge effects, streamline curvature and crossflow. LÄS MER
5. Feedback control and modal structures in transitional shear flows
Sammanfattning : Two types of shear flows are investigated in this thesis; numerical simulations are performed for the analysis and control of the perturbation arising in a boundary layer over a flat plate, whereas PIV measurements are analysed for the investigation of a confined turbulent jet. Modal structures of the flows are identified: the aim is to understand the flow phenomena and to identify reduced-order models for the feedback control design. LÄS MER