Sökning: "steady state solutions"

Visar resultat 1 - 5 av 55 avhandlingar innehållade orden steady state solutions.

  1. 1. An experimental investigation of flow in a Kaplan runner : steady-state and transient

    Författare :Kaveh Amiri; Bjarne Børresen; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

    Sammanfattning : Water turbines are since some years widely used for grid stabilization purposes according to their exceptional load variation capability which gives them the ability to compensate grid fluctuations initiated by the customer’s consumption or intermittent electricity production systems such as wind and solar power. Different renewable power generation technologies can be combined in mini-grids to electrify isolated villages and extend existing grid networks. LÄS MER

  3. 2. Realistic simulations of delta wing aerodynamics using novel CFD methods

    Författare :Stefan Görtz; Arthur Rizzi; Miguel Visbal; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; CFD; aerodynamics; flow physics; steady; unsteady; delta wing; vortical flow; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : The overall goal of the research presented in this thesis is to extend the physical understanding of the unsteady external aerodynamics associated with highly maneuverable delta-wing aircraft by using and developing novel, more efficient computational fluid dynamics (CFD) tools. More specific, the main purpose is to simulate and better understand the basic fluid phenomena, such as vortex breakdown, that limit the performance of delta-wing aircraft. LÄS MER

  4. 3. Mathematical modelling approach to collective decision-making

    Författare :Natalia Zabzina; Denis Gaidashev; Torbjörn Lundh; Uppsala universitet; []
    Nyckelord :collective behaviour; collective decision-making; communication mechanisms; positive feedback; mathematical modelling; bifurcation phenomena; steady state solutions; symmetry breaking; symmetry restoring; diffusion-limited aggregation; fractal dimension;

    Sammanfattning : In everyday situations individuals make decisions. For example, a tourist usually chooses a crowded or recommended restaurant to have dinner. Perhaps it is an individual decision, but the observed pattern of decision-making is a collective phenomenon. LÄS MER

  5. 4. Convergence Acceleration for Flow Problems

    Författare :Henrik Brandén; Sverker Holmgren; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Computational fluid dynamics; convergence acceleration; semicirculant preconditioning; fundamental solutions; Numerical Analysis; Numerisk analys;

    Sammanfattning : Convergence acceleration techniques for the iterative solution of system of equations arising in the discretisations of compressible flow problems governed by the steady state Euler or Navier-Stokes equations is considered. The system of PDE is discretised using a finite difference or finite volume method yielding a large sparse system of equations. LÄS MER

  7. 5. Receptivity of crossflow-dominated boundary layers

    Författare :David Tempelmann; Ardeshir Hanifi; Dan Henningson; Anatoli Tumin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; three-dimensional boundary layers; optimal growth; adjoint solutions; swept wing;

    Sammanfattning : This thesis deals with receptivity mechanisms of three-dimensional, crossflow-dominated boundary layers. The receptivity of two model problems, a swept-flat-plate and a swept-wing boundary layer, is investigated by solving the parabolised stability equations (PSE) as well as by performing direct numerical simulations (DNS). LÄS MER