Sökning: "flat-plate boundary layer"
Visar resultat 1 - 5 av 36 avhandlingar innehållade orden flat-plate boundary layer.
Sammanfattning : Wall transpiration, in the form of wall-normal suction or blowing through a permeable wall, is a relatively simple and effective technique to control the behaviour of a boundary layer. For its potential applications for laminar-turbulent transition and separation delay (suction) or for turbulent drag reduction and thermal protection (blowing), wall transpiration has over the past decades been the topic of a significant amount of studies. LÄS MER
Sammanfattning : Transition delay in boundary-layer flows is achieved via reactive control of flow instabilities, i.e. Tollmien-Schlichting (TS) waves. Adaptive and model-based control techniques are investigated by means of direct numerical simulations (DNS) and experiments. LÄS MER
Sammanfattning : Both optimal disturbances and optimal control are studied by means of numerical simulations for the case of the flat-plate boundary-layer flow. The optimisation method is the Lagrange multiplier technique where the objective function is the kinetic energy of the flow perturbations and the constraints involve the linearised Navier–Stokes equations. LÄS MER
Sammanfattning : Owing to the increased sea transportation of goods, the environmental impacts of this activity are becoming more and more important, since a ship experiences resistance that directly affects its performance and fuel consumption. The growth of marine organisms (fouling) on ship hulls increases the roughness of the hull surface, which in turn causes a rise in ship resistance with a consequent increase in fuel consumption and greenhouse emissions of up to 40%. LÄS MER
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