Sökning: "body-force model"

Hittade 5 avhandlingar innehållade orden body-force model.

  1. 1. Flow Control and Shape Optimization of Intermediate Turbine Ducts for Turbofan Engines

    Författare :Fredrik Wallin; [2008]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; response surface methodology; intermediate turbine duct; vortex generators; turbine intermediate case; endwall contouring; turbine center frame; body-force model; shape optimization; mid-turbine frame; flow control;

    Sammanfattning : Demands on improved efficiency, reduced emissions and lowered noise levels cause a strive towards high by-pass ratios of commercial turbofan engines. This results in an increased radial offset between the high- and low-pressure turbines. Thus the design of the intermediate turbine duct connecting the two turbines becomes more challenging. LÄS MER

  2. 2. Aerodynamic Design and Optimization of Intermediate Ducts for High By-pass Ratio Jet Engines

    Författare :Fredrik Wallin; [2006]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Intermediate transition ducts; vortex generators; S-shaped ducts; response surface methodology; source term model; optimization;

    Sammanfattning : Demands on improved efficiency and reduced noise levels cause a strive toward high by-pass ratio commercial aero engines. This results in multi-spool aero engines with small high-pressure ratio cores and large fans. The low-pressure system has a lower rotational speed and a larger radius than the high-pressure core system. LÄS MER

  3. 3. Effect of drag reducing plasma actuators using LES

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Romain Futrzynski; KTH.; KTH.; [2017]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; drag reduction; plasma actuator; DMD; LES; optimization; pulsating flow; strömningskontroll; motståndsminskning; plasmaaktuator; DMD; LES; optimering; pulserande strömning; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : The work performed in this thesis explores new ways of reducing the drag of ground vehicles. Specifically, the effect of plasma actuators are investigated numerically with the intention to delay separation around a half-cylinder, a geometry chosen to represent a simplified A-pillar of a truck. LÄS MER

  4. 4. Drag reduction using plasma actuators

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Romain Futrzynski; KTH.; KTH.; [2015]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; drag reduction; plasma actuator; DMD; LES; optimization; pulsating flow; strömningskontroll; motståndsminskning; plasma ställdon; DMD; LES; optimering; pulserande flöde; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : This thesis is motivated by the application of active flow control on the cabin of trucks, thereby providing a new means of drag reduction. Particularly, the work presented strives to identify how plasma actuators can be used to reduce the drag caused by the detachment of the flow around the A-pillars. LÄS MER

  5. 5. Numerical optimization of hull/propeller/rudder configurations

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Kaijia Han; [2008]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fuel cost savings; optimization; pressure fluctuation; self-propulsion; RANS; verification and validation; cavitation; open water; lifting surface; hull-propeller-rudder; effective wake; efficiency; aspect ratio; lifting line; interaction;

    Sammanfattning : The new framework of the global economy has stimulated and expanded the shipbuilding and shipping industry, especially in Asia in the twenty-first century. This induces urgent and high requirements on designing and building both conventional and new types of ships with high performance, such as high speed, manoeuvrability, seaworthiness and so on. LÄS MER