Search for dissertations about: "nonlinear instability"

Showing result 1 - 5 of 60 swedish dissertations containing the words nonlinear instability.

2. 1. Aspects of Wave Interaction in Nonlinear Media

   Author : Björn Hall; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear Schrödinger equation; incoherent solitons; partial incoherence; nonlinear wave interaction; Gross-Pitaevskii equation; modulational instability; collective dynamics; Wigner transform; nonlinear guided waves; Bose-Einstein condensation;

   Abstract : Selected aspects of various types of nonlinear wave interaction are investigated. These aspects are studied in terms of models described by Nonlinear Schrödinger equations, mainly analytically and numerically, but also experimentally. READ MORE

4. 2. Theoretical and Experimental Investigations of Nonlinear Flame Instability

   Author : Li-Zheng Ma; Chalmers tekniska högskola; []
   Keywords : 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;

   Abstract : 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. READ MORE

5. 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

6. 4. Nonlinear Theory of Partially Coherent Optical Waves

   Author : Tobias Hansson; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optics; partial coherence; beam collapse; saturable logarithmic media; soliton interaction; dressing method; parabolic beams; Wigner transform; invariants; modulational instability;

   Abstract : Nonlinear effects arise in optics as a consequence of the medium properties being modified by the presence of light. Of particular interest are situations where the effect of the nonlinearity can be described by an intensity dependent refractive index and the subsequent interplay with dispersion and diffraction. READ MORE

7. 5. Electromechanical Instability in Suspended Nanowire-Based NEMS

   Author : Fabio Santandrea; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NEMS; Shuttle instability; Coulomb blockade; Carbon Nanotubes; Electronic Transport; Nonlinear Dynamics;

   Abstract : "Nanoelectromechanical systems'' (NEMS) are a class of nanometer-sized mechanical structures coupled to electronic device of comparable dimensions. Their peculiar features make them interesting both from the technological and fundamental research viewpoints. READ MORE