Sökning: "vortex drag"

Visar resultat 6 - 10 av 30 avhandlingar innehållade orden vortex drag.

  1. 6. Turbulent Boundary Layer Separation and Control

    Författare :Ola Lögdberg; P. Henrik Alfredsson; Jens Fransson; Guido Buresti; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; adverse pressure gradient APG ; flow separation; vortex generators; jet vortex generators; pulsed jet vortex generators; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Boundary layer separation is an unwanted phenomenon in most technical applications, as for instance on airplane wings, ground vehicles and in internal flow systems. If separation occurs, it causes loss of lift, higher drag and energy losses. It is thus essential to develop methods to eliminate or delay separation. LÄS MER

  3. 7. Development of Vortex Filament Method for Wind Power Aerodynamics

    Författare :Hamidreza Abedi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; unsteady aerodynamic load; atmospheric turbulence; fatigue loads; Free wake model; forest canopy; wind turbine; vortex method; large-eddy simulation;

    Sammanfattning : Wind power is currently one of the cleanest and widely distributed renewable energy sources serving as an alternative to fossil fuel generated electricity. Exponential growth of wind turbines all around the world makes it apt for different research disciplines. LÄS MER

  4. 8. Active Flow Control for Drag Reduction of Heavy Vehicles

    Författare :Mohammad El-Alti; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Active and Passive Flow Control; Tilt-rotor wing; Large-eddySimulation; Heavy vehicles; optimization; Full-scale road test; Trucks; Bluff-body; Wake; Drag reduction; Aircrafts; Response surface methodology; Synthetic-jet Actuator;

    Sammanfattning : This thesis considers the aerodynamics of trucks. The work focuses on the aerodynamic drag caused by the wake. Bluff-body flows are dominated by large dissipative vortex-shedding wakes with a low mean pressure compared to the high pressure on their frontal area. LÄS MER

  5. 9. Vane applications and vane induced flow

    Författare :Fredrick Marelius; KTH; []
    Nyckelord :vane; erosion; shore protection; vortex; scour; ;

    Sammanfattning : Vanes are essentially small aspect ratio foils used forguiding sediment, by means of affecting the flow features. Theyare usually placed on the river bed and aligned with an angleof attack to the approach flow, thereby inducing a secondaryflow component that is used for guiding sediment in a desireddirection. LÄS MER

  7. 10. Wakes behind wind turbines - Studies on tip vortex evolution and stability

    Författare :Ylva Odemark; Jens Fransson; Jens Madsen; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind power; aerodynamics; hot-wire anemometry; vortex dynamics;

    Sammanfattning : The increased fatigue loads and decreased power output of a wind turbine placed in the wake of another turbine is a well-known problem when building new wind power farms. In order to better estimate the total power output of a wind power farm, knowledge about the development and stability of wind turbine wakes is crucial. LÄS MER