Sökning: "unsteady"

Visar resultat 21 - 25 av 176 avhandlingar innehållade ordet unsteady.

  1. 21. Flutter in sectored turbine vanes

    Författare :Olga V. Chernysheva; KTH; []
    Nyckelord :turbomachinery; aerodynamics; unsteady CFD; design; flutter;

    Sammanfattning : In order to eliminate or reduce vibration problems inturbomachines without a high increase in the complexity of thevibratory behavior, the adjacent airfoils around the wheel areoften mechanically connected together with lacing wires, tip orpart-span shrouds in a number of identical sectors. Although anaerodynamic stabilizing effect of tying airfoils together ingroups on the whole cascade is indicated by numerical andexperimental studies, for some operating conditions suchsectored vane cascade can still remain unstable. LÄS MER

  3. 22. Experimental Investigation of Velocity Gust in High Pressure Turbines

    Författare :Kai Freudenreich; KTH; []
    Nyckelord :turbomachinery; unsteady aerodynamics; gust; forcing function; forced response; transonic flow; annular cascade; Laser-Two-Focus Anemometer; experiments;

    Sammanfattning : This thesis investigates the unsteady three-dimensional gustfield in high subsonic and transonic turbine stages based onexperimental velocity data. The generation, propagation andinteraction mechanisms of the velocity gust in high pressureturbines are studied. LÄS MER

  4. 23. Analysis of the Unsteady Flow Field of a Passenger Vehicle

    Författare :Lennert Sterken; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wind tunnel; Wake; CFD; Pressure measurements; Extensions; Yaw response; External aerodynamics; Aerodynamic forces;

    Sammanfattning : Political legislation and consumer requirements for a sustainable society require that vehicle manufacturers focus on reduced fuel consumption and lower emissions. Areduction in the overall energy consumption can be directly linked to a decrease of the driving resistance, where the aerodynamic drag significantly contributes at velocities above 70km/h. LÄS MER

  5. 24. A Numerical Study of Reacting Flows Using Finite Rate Chemistry

    Författare :Mohammad Irannezhad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Combustion modeling; Lean blow off; Finite rate chemistry; Inlet boundary condition; Combustion; Lean premixed; Engine configuration; Pulse Detonation Engine; Emissions; URANS; Unsteady phenomena; Flame stabilization; Low Swirl Burner; Large Eddy Simulation; Dynamic flame; Working cycle;

    Sammanfattning : Fossil fuels will remain the main source of energy for mankind in theforeseeable future. Heat released in combustion of fossil fuels is alwaysaccompanied by emission of undesired pollutants. Environmental concernshave led to stringent emission rules for combustion industry speciallyfor reducing the amount of NOx production. LÄS MER

  7. 25. Subjective perception and prediction model of vehicle stability under aerodynamic excitations

    Författare :Arun Kumar; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; human-vehicle interaction; prediction model; drivability; unsteady aerodynamics; Driving simulator; driver perception.; vehicle stability;

    Sammanfattning : The current automotive era is moving towards electrified vehicle propulsion. As a result, an energy efficient vehicle design becomes one of the top priorities. From an aerodynamics point of view, the vehicle should be more streamlined for minimal aerodynamic drag. LÄS MER