Search for dissertations about: "instability"

Showing result 1 - 5 of 728 swedish dissertations containing the word instability.

  1. 1. Instability in Settling Fibres : A Numerical Study

    Author : Feng Zhang; Anders A. Dahlkild; Fredrik Lundell; Mark Martinez; KTH; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; bre suspensions; sedimentation; instability; mixture model; point-particle mode;

    Abstract : Sedimenting suspensions exist in a varity of natural phenomena and industrial applications. It is already observed in experiments that the dilute fibre suspensions experience a concentration instability under gravity at low Reynolds numbers. Initially well-mixed suspensions become inhomogeneous and anisotropic due to this instability. READ MORE

  2. 2. Experimental study of the rotating-disk boundary-layer flow

    Author : Shintaro Imayama; Henrik Alfredsson; Rebecca Lingwood; Benoît Pier; KTH; []
    Keywords : ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fluid mechanics; boundary layer; rotating disk; laminar-turbulent transition; convective instability; absolute instability; secondary instability; crossflow instability; hot-wire anemometry.;

    Abstract : Rotating-disk flow has been investigated not only as a simple model of cross flow instability to compare with swept-wing flow but also for industrial flow applications with rotating configurations. However the exact nature of laminar-turbulent transi- tion on the rotating-disk flow is still major problem and further research is required for it to be fully understood, in particular, the laminar-turbulent transition process with absolute instability. READ MORE

  3. 3. Direct numerical simulations of the rotating-disk boundary-layer flow

    Author : Ellinor Appelquist; Philipp Schlatter; Henrik Alfredsson; Rebecca Lingwood; Christopher Davies; KTH; []
    Keywords : Fluid mechanics; boundary layer; rotating disk; laminar-turbulent transition; convective instability; absolute instability; secondary instability; crossflow instability; direct numerical simulations; Teknisk mekanik; Engineering Mechanics;

    Abstract : This thesis deals with the instabilities of the incompressible boundary-layer flow that is induced by a disk rotating in otherwise still fluid. The results presented are mostly limited to linear instabilities derived from direct numerical simulations (DNS) but with the objective that further work will focus on the nonlinear regime, providing greater insights into the transition route to turbulence. READ MORE

  4. 4. Radar Signatures of Auroral Plasma Instability

    Author : Nicola Schlatter; Nickolay Ivchenko; Anja Stromme; KTH; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Ionosphere; Particle Precipitation; Instability; Plasma Turbulence; Physics; Fysik;

    Abstract : Incoherent scatter radars are powerful ground based instruments for ionospheric measurements. By analysis of the Doppler shifted backscatter spectrum, containing the signature of electrostatic plasma waves, plasma bulk properties are estimated. READ MORE

  5. 5. Co-rotational beam elements in instability problems

    Author : Jean-Marc Battini; KTH; []
    Keywords : instability; co-rotational mehtod; branch-switching; beam element; warping; plastic buckling. post-bifurcation; NATURAL SCIENCES; NATURVETENSKAP;

    Abstract : The purpose of the work presented in this thesis is to implement co-rotational beam elements and branch-switching procedures in order to analyse elastic and elastoplasticinstability problems. For the 2D beam elements, the co-rotational framework is taken from Crisfield [23]. READ MORE