Sökning: "turbulent flöde"

Visar resultat 1 - 5 av 21 avhandlingar innehållade orden turbulent flöde.

  1. 1. High Performance Finite Element Methods with Application to Simulation of Vertical Axis Wind Turbines and Diffusion MRI

    Författare :Van Dang Nguyen; Johan Hoffman; Johan Jansson; Mats Larson; KTH; []
    Nyckelord :High performance finite element method; computational diffusion MRI; turbulent flow; vertical axis wind turbine; Cloud computing.; högprestanda finita elementmetod; beräkningsdiffusionsmagnetresonanstomografi; turbulent flöde; vertikalaxlad vindturbin; datormolnberäkning; Tillämpad matematik och beräkningsmatematik; Applied and Computational Mathematics; Biological Physics; Biologisk fysik; Computer Science; Datalogi; Engineering Mechanics; Teknisk mekanik; Mathematics; Matematik; Biological and Biomedical Physics; Biologisk och biomedicinsk fysik;

    Sammanfattning : Finite element methods have been developed over decades, and together with the growth of computer power, they become more and more important in dealing with large-scale simulations in science and industry.The objective of this thesis is to develop high-performance finite element methods, with two concrete applications: computational fluid dynamics (CFD) with simulation of turbulent flow past a vertical axis wind turbine (VAWT), and computational diffusion magnetic resonance imaging (CDMRI). LÄS MER

  3. 2. Laminar and turbulent particle laden flows : a numerical and experimental study

    Författare :Seyed Hamid Tabaeikazerooni; Luca Brandt; Jeanette Hussong; Raffaella Ocone; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Suspension flow; inertial effect; turbulent duct flow; finite-size particles; Immersed Boundary Method IBM ; Astigmatism Particle Tracking Velocimetry APTV ; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : Particle laden flows are widespread in nature and in industrial applications. Dust storms, geophysical flows, pharmaceutical processes, fluidized beds and blood flow are only a few examples. Both global and local properties of a particle laden flow may alter significantly in comparison to the corresponding single phase flow. LÄS MER

  4. 3. Shapes of pipes

    Författare :Valerio Lupi; Philipp Schlatter; Ramis Örlü; Jean-Christophe Robinet; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Global stability; curved pipes; secondary flow; wall-bounded turbulence; Global stabilitet; krökta rör; sekundärflöde; turbulens; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Curved pipes are ubiquitous in several industrial applications and biological systems. The study of flows through these configurations is therefore of significant practical interest.In the present thesis, the modal stability of flows in both toroidal and spatially developing bent pipes is investigated to understand the onset of transition. LÄS MER

  5. 4. Stability and transition on wind turbine blades

    Författare :Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER

  7. 5. Uncertainty quantification for time varying quantities in turbulent flows

    Författare :Donnatella Xavier; Philipp Schlatter; Saleh Rezaeiravesh; Ricardo Vinuesa; David Moxey; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; uncertainty; variance estimator; autoregressive models; turbulence; computational fluid dynamics; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Quantification of uncertainty in results is crucial in both experiments and simulations of turbulence, yet this practice is notably underutilized. This thesis project delves into statistical tools within the framework of uncertainty quantification to systematically quantify uncertainties that occur in the time varying quantities of turbulence. LÄS MER