Sökning: "fluid limit"

Visar resultat 21 - 25 av 127 avhandlingar innehållade orden fluid limit.

  1. 21. Flow instabilities in centrifugal compressors at low mass flow rate

    Författare :Elias Sundström; Mihai Mihaescu; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Centrifugal compressor; flow instabilities; rotational flows; rotating stall; surge; compressible Large Eddy Simulation; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : A centrifugal compressor is a mechanical machine with purpose to convert kineticenergy from a rotating impeller wheel into the fluid medium by compressingit. One application involves supplying boost air pressure to downsized internalcombustion engines (ICE). LÄS MER

  3. 22. Aspects of adaptive mesh refinement in the spectral element method

    Författare :Nicolas Offermans; Philipp Schlatter; Ananias Tomboulides; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Error estimators; mesh refinement; adaptivity; spectral element method; algebraic multigrid method; NACA4412; periodic hill case.; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : This thesis deals with the improvement of the efficiency of numerical simulations in computational fluid dynamics. Some of the limitations of current algorithms on future exascale supercomputers are addressed with the main goal of using adaptive mesh refinement for the simulation of turbulent and three-dimensional flows. LÄS MER

  4. 23. Acoustical Measurements of Material Nonlinearity and Nonequilibrium Recovery

    Författare :Kristian Haller; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear acoustics; nondestructive testing; activation density; slow dynamics; nonequilibrium recovery; resonance frequency; nonlinear wave modulation spectroscopy; harmonic generation; trapped modes; open resonator; sweep rate; constant strain sweep;

    Sammanfattning : A damaged material or a material with non perfect atomic geometry, dislocations or cracks, exhibits two types of characteristic responses to acoustic excitations. First is the fast nonlinear dynamics response that is present as long as the material is excited. As soon as the excitation stops the response disappear. LÄS MER

  5. 24. Tyre aerodynamics of passenger vehicles

    Författare :Erik Josefsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; drag; wind tunnel; tyres; aerodynamics; wheels;

    Sammanfattning : To decelerate climate change and limit global warming, there is a need for reducing the environmental impact of vehicles, which can be achieved by increasing their energy efficiency. For a passenger vehicle, one of the largest resistive forces is aerodynamic drag. LÄS MER

  7. 25. Experimental and Numerical Investigations of Flames Stabilized by Swirl Flow and Bluff-body:Flame Structures and Flame Instabilities

    Författare :Yiheng Tong; Kraftverksteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flame structures; Flame instabilities; Blowout limits; Flashback; Swirl Flow; Bluff-body; Chemiluminescence; PIV;

    Sammanfattning : Combustion and its control are essential to our existence on this planet since we knew it. Nowadays, the largest share of the world’s electricity and most of our transportation systems are powered by combustion. In addition, industrial processes also rely heavily upon combustion. LÄS MER