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Visar resultat 1 - 5 av 41 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Study of Supersonic Jet Noise Reduction using LES

    Författare :Haukur Hafsteinsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; G3D; Supersonic Jet; PIV; CD-nozzle; CFD; Compressible flow; CAA; Noise Reduction; LES; Flow Control;

    Sammanfattning : Increases in air traffic and denser population around airports have led to stricterregulations on aircraft noise. High noise levels from high-speed aircraft can causehearing damage in pilots and the airfield personnel. The engine is the main sourceof noise of all jet aircraft and is therefore a key component for improvement. LÄS MER

  3. 2. Numerical Simulation of Turbulent Flows for Turbine Blade Heat Transfer Applications

    Författare :Jonas Larsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; k-.omega.; k-.epsilon.; explicit Runge-Kutta; finite volume; turbine; numerical method; non-linear; Navier-Stokes; supersonic; two-equation; external heat transfer; stagnation flow; two-dimensional; transition; low-Reynolds; turbulence model; impulse blade;

    Sammanfattning : Turbine blade heat transfer is an important engineering problem characterized by complex flow fields and high turbulence levels. This thesis is focused on using a full Navier-Stokes solver with two-equation eddy-viscosity models to predict external heat-transfer in single-stage, linear, two-dimensional uncooled turbine cascades. LÄS MER

  4. 3. A Panel Method for Supersonic Flow

    Författare :David Pettersson; Per Weinerfeldt; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MATHEMATICS; MATEMATIK;

    Sammanfattning : Supersonic airflow is usually described by a nonlinear hyperbolic system of equations. In this thesis we consider an aircraft represented by a union of thin plates orthogonal to the direction of Right, and describe the derivation of an approximate linear model for the airflow around it. The linear model is reduced to a system of integral equations. LÄS MER

  5. 4. Large Eddy Simulation for the Analysis of Supersonic Jet Noise Suppression Devices

    Författare :Markus Olander Burak; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluidic injection; mixer-ejector; jet noise; Kirchhoff; forward flight effects; LES; acoustic liner; supersonic turbulent jets; broadband time-domain impedance boundary condition; chevrons; shock-associated noise; CAA; aeroacoustics;

    Sammanfattning : Stricter noise regulations for commercial and military aircraft have increased interest in noise reduction techniques within the aerospace industry. To meet the requirements, new noise suppression technologies have to be developed and numerical methods need to be validated and possibly improved for the correct assessment of these technologies. LÄS MER

  7. 5. Modal Analysis of Supersonic Flow Separation in Nozzles

    Författare :Ragnar Larusson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Separated Nozzle Flow; Dynamic Mode Decomposition; Hybrid RANSLES; CFD; Modal Analysis; Arnoldi;

    Sammanfattning : Operating a convergent-divergent nozzle under overexpanded conditions can lead to supersonic flow separation in the divergent section of the nozzle. In this case, an attached oblique shock wave forms at the separation base. LÄS MER