Search for dissertations about: "kelvin-helmholtz"

Showing result 1 - 5 of 19 swedish dissertations containing the word kelvin-helmholtz.

  2. 1. New Perspectives on Solar Wind-Magnetosphere Coupling

    Author : Torbjörn Sundberg; Lars Blomberg; Judy Cumnock; Masaki Fujimoto; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; magnetosphere; ionosphere; mercury; kelvin-helmholtz; Electrophysics; Elektrofysik;

    Abstract : The streaming plasma in the solar wind is a never ending source of energy, plasma, and momentum for planetary magnetospheres, and it continuously drives large-scale plasma convection systems in our magnetosphere and over our polar ionosphere. This coupling between the solar wind and the magnetosphere is primarily explained by two different processes: magnetic reconnection at high latitudes, which interconnects the interplanetary magnetic field (IMF) with the planetary dipole field, and low-latitude dynamos such as viscous interaction, where the streaming plasma in the solar wind may trigger waves and instabilities at the flanks of the magnetosphere, and thereby allow solar wind plasma to enter into the system. READ MORE

  4. 2. Solitary waves and enhanced incoherent scatter ion lines

    Author : Jonas Ekeberg; Lars Eliasson; Kristof Stasiewicz; Jan Trulsen; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; plasma waves and instabilities; nonlinear phenomena; solitons and solitary waves; ionosphere; Sun: corona; incoherent scatter radar; MHD; plasmavågor och instabiliteter; ickelinjära fenomen; solitoner och solitära vågor; jonosfär; solen: korona; inkoherent spridningsradar; MHD; Geocosmophysics and plasma physics; Geokosmofysik och plasmafysik; Space physics; Rymdfysik; Plasma physics; Plasmafysik; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos; fysik; Physics; rymd- och plasmafysik; Space and Plasma Physics;

    Abstract : This thesis addresses solitary waves and their significance for auroral particle acceleration, coronal heating and incoherent scatter radar spectra. Solitary waves are formed due to a balance of nonlinear and dispersive effects. READ MORE

  5. 3. Structures and processes in the Mercury magnetosphere

    Author : Elisabet Liljeblad; Tomas Karlsson; Anita Kullen; Haje Korth; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mercury; MESSENGER; magnetosphere; processes; structures; Electrical Engineering; Elektro- och systemteknik;

    Abstract : The mechanisms involved in the transfer of mass and energy from the solar wind to any planetary magnetosphere is considered an important topic in space physics. With the use of the Mercury spacecraft MESSENGER's data, it has been possible to study these processes in an environment different, yet similar, to Earth's. READ MORE

  6. 4. Turbulent flows over permissive boundaries and porous walls

    Author : Seyed Morteza Habibi Khorasani; Shervin Bagheri; Geert Brethouwer; Alfredo Soldati; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Direct numerical simulations; wall-bounded turbulence; flow control; porous walls; heat transfer; Direkta numeriska simuleringar; väggbunden turbulens; flödeskontroll; porösa väggar; värmeöverföring; Teknisk mekanik; Engineering Mechanics;

    Abstract : This thesis investigates how in wall-bounded turbulent flows changes to the wall can induce changes in the flow. To this end, we investigate the use of wall boundary conditions meant to mimic the effect of textured surfaces. READ MORE

  7. 5. Stability and transition on wind turbine blades

    Author : Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

    Abstract : 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. READ MORE