Sökning: "Aircrafts"

Visar resultat 1 - 5 av 36 avhandlingar innehållade ordet Aircrafts.

  1. 1. Active Flow Control for Aircrafts and Heavy Vehicles

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

    Sammanfattning : Bluff-body flows are dominated by large dissipative vortex-shedding wakes with low mean pressure compared to the high pressure on their frontal area. This induced pressure difference is the major contribution to the total aerodynamic drag. LÄS MER

  3. 2. 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

  4. 3. Mathematical Modeling, Optimization and Scheduling of Aircraft's Components Maintenance and of the Maintenance Workshop

    Författare :Gabrijela Obradovic; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Simultaneous Scheduling; Contracting Forms; Mathematical modelling; Maintenance Optimization; Workshop Scheduling; Multi-Objective Optimization; Mixed-Binary Linear Optimization Model;

    Sammanfattning : This research concerns the simultaneous scheduling of preventive maintenance for a fleet of aircraft and their common components along with the maintenance workshop, to which the components are sent for repair. The problem arises from an industrial project with the Swedish aerospace and defence company Saab. LÄS MER

  5. 4. Plasticity modelling of nickel based super alloy Alloy 718

    Författare :Ted Sjöberg; Paul Åkerström; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : The ever growing demand on reduced fuel consumption in modern aircrafts puts high requirements on manufacturers to reduce weight in all parts of the aircraft. With a total weight of up to one fifth of an aircraft’s total operating weight, ways to decrease the weight of the engine systems are continuously sought. LÄS MER

  7. 5. Iterative solution of Maxwell's equations in frequency domain

    Författare :Martin Nilsson; Per Lötstedt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

    Sammanfattning : We have developed an iterative solver for the Moment Method. It computes a matrix–vector product with the multilevel Fast Multipole Method, which makes the method scale with the number of unknowns. The iterative solver is of Block Quasi-Minimum Residual type and can handle several right-hand sides at once. LÄS MER