Sökning: "forcing"

Visar resultat 1 - 5 av 232 avhandlingar innehållade ordet forcing.

  1. 1. Reduction of Aerodynamic Forcing inTransonic Turbomachinery : Numerical Studies on Forcing Reduction Techniques

    Författare :Florian Fruth; Torsten Fransson; Damian Vogt; Ronald Mailach; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Forced Response; Aerodynamic Forcing; Efficiency; Blade Count Ratio; Clocking;

    Sammanfattning : Due to more and more aggressive designs in turbomachinery, assuring the structural integrity of its components has become challenging. Also influenced by this trend is blade design, where lighter and slimmer blades, in combination with higher loading, lead to an increased risk of failure, e.g. in the form of blade vibration. LÄS MER

  2. 2. Causal links of past climate change in Coupled Model Intercomparison Project Phase 5 climate models

    Författare :Thanh Le; MERGE - ModElling the Regional and Global Earth system; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; solar forcing; volcanic forcing; greenhouse gases radiative forcing; Granger causality; near-surface air temperature; ENSO; IOD; CMIP5; North Atlantic;

    Sammanfattning : The climate system is influenced by various external forcings (e.g. volcanic forcing, solar forcing and change of greenhouse gas concentrations) and its own internal climate variability. LÄS MER

  3. 3. Studies on instability and optimal forcing of incompressible flows

    Författare :Mattias Brynjell-Rahkola; Dan S. Henningson; Ardeshir Hanifi; Philipp Schlatter; François Gallaire; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hydrodynamic stability; optimal forcing; resolvent operator; Laplace preconditioner; spectral element method; eigenvalue problems; inverse power method; direct numerical simulations; Falkner–Skan–Cooke boundary layer; localized roughness; crossflow vortices; Blasius boundary layer; localized suction; helical vortices; lid-driven cavity; cylinder flow; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : This thesis considers the hydrodynamic instability and optimal forcing of a number of incompressible flow cases. In the first part, the instabilities of three problems that are of great interest in energy and aerospace applications are studied, namely a Blasius boundary layer subject to localized wall-suction, a Falkner–Skan–Cooke boundary layer with a localized surface roughness, and a pair of helical vortices. LÄS MER

  4. 4. Large Eddy Simulation of Impinging Jets

    Författare :Thomas Hällqvist; Laszlo Fuchs; Pierre Sagaut; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Impinging jet; large eddy simulation; heat transfer; vortex formation; circular jet; forcing; inflow conditions; implicit modeling.; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : This thesis deals with Large Eddy Simulation (LES) of impinging air jets. The impinging jet configuration features heated circular jets impinging onto a flat plate. The problem addressed here is of generic nature, with applications in many engineering devices, such as cooling of components in gas turbines, in cars and electronic devices. LÄS MER

  5. 5. Solar Forcing of Nitric Oxide in the Upper Atmosphere

    Författare :Koen Hendrickx; Linda Megner; Jörg Gumbel; Bernd Funke; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; nitric oxide; NO; mesosphere; lower thermosphere; MLT; energetic particle precipitation; EPP; medium energy electrons; MEE; SOFIE; SNOE; WACCM; POES; Atmospheric Sciences and Oceanography; atmosfärvetenskap och oceanografi;

    Sammanfattning : The forcing of the Sun on Earth's atmosphere manifests itself via solar radiation and energetic particle precipitation (EPP), which variations are most noticeable in the upper regions of the atmosphere. A key species in the lower thermosphere, which is influenced by solar forcing, is nitric oxide (NO). LÄS MER