Sökning: "nonlinear hydrodynamic instability"

Hittade 4 avhandlingar innehållade orden nonlinear hydrodynamic instability.

  1. 1. Theoretical and Experimental Investigations of Nonlinear Flame Instability

    Författare :Li-Zheng Ma; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; nonlinear hydrodynamic instability; flame propagation and stretch effects; shock induced flame instability; tulip flame formation; interface tracking; the Schlieren technique; level set approach;

    Sammanfattning : Flame instability is both important and difficult to understand. Mechanisms of instability are complex, because instability often involves an interaction between several different physical phenomena, such as an unsteady chemical reaction, unsteady flame propagation generating an unsteady flow, acoustic waves or shock waves. LÄS MER

  3. 2. Numerical Study of Cellular Instability in Burner Stabilized Adiabatic Laminar Premixed Flames

    Författare :Jiangfei Yu; Strömningsteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Detailed Numerical Simulation; Cellular premixed flame; Hydrogen; Oxy-fuel; Heat-flux burner; Hydrodynamic instability; Diffusive-thermal instability; Nonlinear flame dynamics.;

    Sammanfattning : The thesis deals with experiments and numerical simulations of adiabatic laminar premixed flames anchored to a heat-flux burner using different mixtures under various operating conditions. The aim is to obtain a better understanding of cellular instability in heat-flux burner anchored flames. LÄS MER

  4. 3. Cases of coupled vibrations and prametric instability in rotating machines

    Författare :Jean-Claude Luneno; Ilmar Santos; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : The principal task in this research project was to analyse the causes and consequences of coupled vibrations and parametric instability in hydropower rotors; where both horizontal and vertical machines are involved. Vibration is a well-known undesirable behavior of dynamical systems characterised by persistent periodic, quasi-periodic or chaotic motions. LÄS MER

  5. 4. Coupled vibrations in horizontal and vertical rotor-bearings systems

    Författare :Jean-Claude Luneno; Magnus Karlberg; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Technology - Engineering mechanics; Teknikvetenskap - Teknisk mekanik; Hållfasthetslära; Solid Mechanics;

    Sammanfattning : For dynamical systems having several degrees of freedom, motion in one direction can induce motion in the other and/or vice versa. This means that there is a certain coupling between these two motions. Coupling can in some cases be a source of instability that causes self-excited vibrations in rotating machinery. LÄS MER