Search for dissertations about: "Nonlinear flow"

Showing result 1 - 5 of 152 swedish dissertations containing the words Nonlinear flow.

  2. 1. Acoustic characterization of orifices and perforated liners with flow and high-level acoustic excitation

    Author : Lin Zhou; Hans Bodén; Wim De Roeck; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bias Flow; Grazing Flow; Nonlinear Acoustics; Acoustic Impedance; Impedance Eduction; Single Mode Straightforward Method; Uncertainty Analysis; LEE; LNSE; Järnvägsgruppen - Ljud och vibrationer; Järnvägsgruppen - Ljud och vibrationer;

    Abstract : This thesis is motivated by the need for noise control in aircraft engine with orifices and perforated liner. The presence of high-level acoustic excitation, different flow situations either bias flow, grazing flow or any combination in the aircraft engine, makes the acoustic behavior complex due to the interaction between sound and flow over the lined wall. READ MORE

  4. 2. Nonlinear dynamics in transitional wall-bounded flows

    Author : Miguel Beneitez Galan; Dan S. Henningson; Philipp Schlatter; Yohann Duguet; Tobias Schneider; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering Mechanics; Teknisk mekanik;

    Abstract : This thesis focuses on numerical studies of subcritical transition to turbulence in shear flows. The thesis employs a framework based on nonlinear dynamics in the subsequent studies. The geometrical approach to subcritical transition pivots the concepts of edge manifold and edge state. READ MORE

  5. 3. Potential Flow Panel Methods for the Calculation of Free-surface Flows with Lift

    Author : Carl-Erik Janson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; desingularized; shape optimization; Rankine source; waves; OCTOPUS; dipole; MMA; Dawson operator; boundary layer; vortex; Method of Moving Asymptotes; nonlinear; sailing yacht; four point operator; surface piercing wing; Navier-Stokes; numerical method; lift force; raised panel method; discrete Fourier transform; collocation point shift; potential flow; CFD; free surface; induced drag; SHIPFLOW; dispersion; damping; analytical method; hydrofoil;

    Abstract : Two non-linear Rankine-source panel methods are developed and implemented in the same computer code. The first method uses a four-point upwind operator on the free-surface to compute the velocity derivatives and to enforce the radiation condition while the second method uses an analytical expression for the velocity derivatives and a collocation point shift one panel upstream to prevent upstream waves. READ MORE

  6. 4. Adjoint based control and optimization of aerodynamic flows

    Author : Mattias Chevalier; KTH; []
    Keywords : transition control; flow control; nonlinear optimal control; boundary layer flow; Falkner-Skan-Cooke flow; quasi-1D flow; shape optimization; adjoint equations; DNS;

    Abstract : .... READ MORE

  7. 5. Learning flow functions : architectures, universal approximation and applications to spiking systems

    Author : Miguel Aguiar; Karl H. Johansson; João Sousa; Maarten Schoukens; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Abstract : Learning flow functions of continuous-time control systems is considered in this thesis. The flow function is the operator mapping initial states and control inputs to the state trajectories, and the problem is to find a suitable neural network architecture to learn this infinite-dimensional operator from measurements of state trajectories. READ MORE