Sökning: "pulsation"

Visar resultat 6 - 10 av 31 avhandlingar innehållade ordet pulsation.

  1. 6. Shapes of pipes

    Författare :Valerio Lupi; Philipp Schlatter; Ramis Örlü; Jean-Christophe Robinet; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Global stability; curved pipes; secondary flow; wall-bounded turbulence; Global stabilitet; krökta rör; sekundärflöde; turbulens; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Curved pipes are ubiquitous in several industrial applications and biological systems. The study of flows through these configurations is therefore of significant practical interest.In the present thesis, the modal stability of flows in both toroidal and spatially developing bent pipes is investigated to understand the onset of transition. LÄS MER

  3. 7. On Fluid Power Pump and Motor Design : Tools for Noise Reduction

    Författare :Liselott Ericson; Jan-Ove Palmberg; Kalevi Huhtala; Linköpings universitet; []
    Nyckelord :;

    Sammanfattning : Noise and vibration are two of the main drawbacks with fluid power  systems. The increasing requirements concerning working environment as well as machines' impact on surroundings put components and systems to harder tests. The surrounding machines, e.g. LÄS MER

  4. 8. Magnetic and Chemical Structures in Stellar Atmospheres

    Författare :Oleg Kochukhov; Nikolai Piskunov; Georges Michaud; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; chemically peculiar stars; high-resolution spectroscopy; magnetic fields; Doppler imaging; rapidly oscillating Ap stars; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Astronomy; Astronomi;

    Sammanfattning : We present an investigation of the magnetic field geometries and inhomogeneous distribution of chemical elements in the atmospheres of peculiar A and B stars. Our study combines high-quality spectroscopic and spectropolarimetric stellar observations with the development and application of novel techniques for theoretical interpretation of the shapes and variability of stellar line profiles. LÄS MER

  5. 9. 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

  7. 10. Aerothermodynamics and exergy analysis in turbocharger radial turbine

    Författare :Shyang Maw Lim; Mihai Mihaescu; Anders Dahlkild; Ricardo Martinez-Botas; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; pulsatile exhaust flow; turbine; turbocharger; Detached Eddy Simulation; heat transfer; exergy; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Coupling of turbomachine to reciprocating automotive engine in turbocharging leads to complex fluid flow and thermal characteristics in the turbine. Some undesirable characteristics include heat transfer, flow pulsation and secondary flow due to the complex geometry of the upstream exhaust manifold. LÄS MER