Sökning: "Turbulent flows"

Visar resultat 16 - 20 av 284 avhandlingar innehållade orden Turbulent flows.

  1. 16. Large Eddy Simulation of Turbulent Swirling Flows and Turbulent Premixed Combustion

    Författare :Ping Wang; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluid dynamics; Gases; flamelet model; flame wrinkle; large eddy simulation; vortex breakdown; turbulent premixed combustion; level set G-equation; swirling flow; plasmas; Gaser; fluiddynamik; plasma; Energy research; Energiforskning;

    Sammanfattning : With the increasing concerns about our environment and human health, more and more stringent emission limits have been specified. These adopted and still coming emission limits require and promote more accurate, less experiential methods to design and develop the combustors. LÄS MER

  3. 17. From irrotational flows to turbulent dynamos

    Författare :Fabio Del Sordo; Axel Brandenburg; Mordecai-Mark Mac Low; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; astrophysics; magnetic fields; insterstellar medium; MHD; dynamo; turbulence; instability; Astronomy; astronomi;

    Sammanfattning : Many of the celestial bodies we know are found to be magnetized:the Earth, many of the planets so far discovered, the Sun and other stars,the interstellar space, the Milky Way and other galaxies.The reason for that is still to be fully understood, and this work is meant to be a step in that direction. LÄS MER

  4. 18. Linear and non-linear dynamics of non-autonomous flows

    Författare :J. Simon Kern; Dan S. Henningson; Ardeshir Hanifi; Peter J. Schmid; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-dependent flows; linear stability; non-linear dynamics; Floquet analysis; optimally time-dependent modes; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Fluid flows subject to time-dependent external forces or boundary conditions are ubiquitous in biology and technical applications. Whether one considers birds flying by flapping their wings or the gust response of wind turbines, the flow is non-autonomous. LÄS MER

  5. 19. Transition delay in boundary-layer flows via reactive control

    Författare :Nicolò Fabbiane; Dan S. Henningson; Shervin Bagheri; Denis Sipp; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; drag reduction; net energy saving; adaptive control; model-based control; optimal control; flat-plate boundary layer; laminar-to- turbulent transition; plasma actuator; direct numerical simulation; in-flight experiments; strömningsstyrning; friktionsreduktion; netto energibesparing; adaptiv styrning; modellbaserad styrning; optimal kontroll; gränsskikt öve en plan platta; laminärt till turbulent omslag; plasma aktuator; DNS; flyg prov; Engineering Mechanics; Teknisk mekanik;

    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

  7. 20. Studies of Transient and Pulsating flows with application to Hydropower

    Författare :Joel Sundström; Michel Cervantes; Mehdi Seddighi; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent flows; Pipe flow; Unsteadiness; Friction modeling; Strömningslära; Fluid Mechanics;

    Sammanfattning : The rotational motion of a hydraulic turbine runner makes pulsating flows ubiquitous in different locations of the machine. The cyclic loading thus induced may generate large pressure forces acting periodically on both stationary and rotating parts. LÄS MER