Search for dissertations about: "Free stream turbulence"

Showing result 1 - 5 of 47 swedish dissertations containing the words Free stream turbulence.

  1. 1. Edge states and transition to turbulence in boundary layers

    University dissertation from KTH Royal Institute of Technology

    Author : Taras Khapko; Dan Henningson; Philipp Schlatter; Yohann Duguet; Rich Kerswell; [2016]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer; transition to turbulence; direct numerical simulation; edge state; free-stream turbulence; bypass transition; probabilistic cellular automaton; turbulence at the onset; laminar–turbulent coexistence; laminarisation; Teknisk mekanik; Engineering Mechanics;

    Abstract : The focus of this thesis is the numerical study of subcritical transition to turbulence in boundary-layer flows. For the most part, boundary layers with uniform suction are considered. Constant homogeneous suction counteracts the spatial growth of the boundary layer, rendering the flow parallel. READ MORE

  2. 2. Gas Exchange over Aquatic Interfaces and its Importance for Greenhouse Gas Emission

    University dissertation from Uppsala : Acta Universitatis Upsaliensis

    Author : Jovana Kokic; Sebastian Sobek; Erik Sahlée; Marcus B. Wallin; Anne Ojala; [2017]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; gas exchange; lake; stream; lake sediment; headwaters; carbon dioxide; methane; greenhouse gas emission; carbon; turbulence; Biology with specialization in Limnology; Biologi med inriktning mot limnologi;

    Abstract : Aquatic ecosystems play a substantial role in global cycling of carbon (C), despite covering only about 4% of the earth surface. They emit large amounts of greenhouse gases (GHG) to the atmosphere, comparable to the amount of C stored annually in terrestrial ecosystems. In addition, C can be buried in lake sediments. READ MORE

  3. 3. On stability, transition and turbulence in three-dimensional boundary-layer flows

    University dissertation from KTH Royal Institute of Technology

    Author : Seyed Mohammd Hosseini; Ardeshir Hanifi; Spencer Sherwin; [2015]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional bound- ary layers; crossflow instability; roughness control; freestream turbulence; sec- ondary instability; transition; turbulence;

    Abstract : A lot has changed since that day on December 17, 1903 when the Wright brothers made the first powered manned flight. Even though the concepts behind flying are unaltered, appearance of stat-of-the-art modern aircrafts has undergone a massive evolution. READ MORE

  4. 4. Transitional boundary layers caused by free-stream turbulence

    University dissertation from Stockholm : KTH Royal Institute of Technology

    Author : Shahab Shahinfar; Jens Fransson; Johan Westin; [2011]

    Abstract : The present measurement campaign on the free-stream turbulence (FST) induced boundary layer transition scenario has provided a unique set of experimental data, with potential to enhance the understanding of the eect of the free-stream turbulence characteristic length scales on the transition location and not only the turbulence intensity, which has been the focus in most previous studies. Recent investigations where the turbulence intensity has been kept essentially constant, while the integral length scale has been changed, show that the transition location is advanced for increasing length scale. READ MORE

  5. 5. Receptivity of Boundary-Layer Flows over Flat and Curved Walls

    University dissertation from Stockholm : KTH

    Author : Lars-Uve Schrader; Luca Brandt; Dan Stefan Henningson; Gregoire Casalis; [2010]
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary-layer receptivity; laminar-turbulent transition; swept-plate boundary layer; Görtler flow; leading-edge effects; swept-wing flow; crossflow vortices; Görtler rolls; disturbance streaks; wall roughness; free-stream turbulence; TECHNOLOGY Engineering mechanics Fluid mechanics; TEKNIKVETENSKAP Teknisk mekanik Strömningsmekanik;

    Abstract : 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. READ MORE