Sökning: "Separated flow"

Visar resultat 1 - 5 av 166 avhandlingar innehållade orden Separated flow.

  1. 1. Modal Decomposition of Separated Nozzle Flow

    Författare :Ragnar Larusson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Arnoldi; axisymmetric convergent-divergent nozzle; Mode Decomposision; Flow Separation; Resonance.; Dynamic Mode Decomposision; Computational Fluid Dynamics;

    Sammanfattning : The applicability of two different eigenvalue algorithms coupled with an axisymmetric RANS solver to predict the eigenmodes of separated supersonic flow inside an axisymmetric convergent-divergent nozzle was investigated. These are the Arnoldi and the Dynamic Mode Decomposition (DMD) algorithms, respectively. LÄS MER

  3. 2. Turbulent Boundary Layer Separation and Control

    Författare :Ola Lögdberg; P. Henrik Alfredsson; Jens Fransson; Guido Buresti; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; adverse pressure gradient APG ; flow separation; vortex generators; jet vortex generators; pulsed jet vortex generators; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Boundary layer separation is an unwanted phenomenon in most technical applications, as for instance on airplane wings, ground vehicles and in internal flow systems. If separation occurs, it causes loss of lift, higher drag and energy losses. It is thus essential to develop methods to eliminate or delay separation. LÄS MER

  4. 3. Numerical investigation of the flow and instabilities at part-load and speed-no-load in an axial turbine

    Författare :Jelle Kranenbarg; Michel Cervantes; Lisa Prahl Wittberg; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Speed-no-load; vortical flow structures; flow instabilities; rotating stall; mitigation; independent guide vanes; axial turbine; swirling flow; off design operation; URANS; parametric study; blade clearance; head losses; diffusor; GEKO model; flow separation; hydraulic turbine; Strömningslära; Fluid Mechanics;

    Sammanfattning : Global renewable energy requirements rapidly increase with the transition to a fossil-free society. As a result, intermittent energy resources, such as wind- and solar power, have become increasingly popular. However, their energy production varies over time, both in the short- and long term. LÄS MER

  5. 4. Experimental Studies of Separated Flow and Heat Transfer in a Ribbed Channel

    Författare :Lei Wang; Värmeöverföring; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Energiforskning; plasma; Energy research; fluiddynamik; Gaser; fluid dynamics; plasmas; Gases; Particle image velocimetry; Liquid crystal thermography; ribbed channel; heat transfer; turbulence properties; separated flow; coherent structures;

    Sammanfattning : The main concern of this thesis is to experimentally investigate the turbulent flow and heat transfer in a ribbed channel. Such flows are encountered in many engineering applications, e.g., gas turbine cooling. LÄS MER

  7. 5. Numerical methods for load and response prediction for use in acoustic fatigue

    Författare :Johan Nilsson; Byggnadsmekanik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustic fatigue; Sonic fatigue; Computational Fluid Dynamics; Large Eddy Simulation; Finite Element Method; Random response analysis; Separated flow; High Re; Backward-facing step; Fence flow; Aircraft; Proper Orthogonal Decomposition; Acoustic fatigue; Sonic fatigue; Computational Fluid Dynamics; Large Eddy Simulation; Finite Element Method; Random response analysis; Separated flow; High Re; Backward-facing step; Fence flow; Aircraft; Proper Orthogonal Decomposition;

    Sammanfattning : Acoustic fatigue can occur in structural elements of an aircraft exposed to very high sound pressures. To deal with acoustic fatigue, mainly empirical methods have been applied and often late in the design phase. Current design guidelines have three main limitations. First, they do not say anything about the load intensities. LÄS MER