Sökning: "self-similarity"

Visar resultat 1 - 5 av 14 avhandlingar innehållade ordet self-similarity.

  1. 1. A Non-Gaussian Limit Process with Long-Range Dependence

    Författare :Raimundas Gaigalas; Ingemar Kaj; Esko Valkeila; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematical statistics; long-range dependence; traffic modelling; arrival process; self-similarity; heavy tails; fractional Brownian motion; stable processes; renewal processes; independently scattered random measure; weak convergence; 60F17; 60G18; 90B18; 60K05 ; Matematisk statistik; Mathematical statistics; Matematisk statistik;

    Sammanfattning : This thesis, consisting of three papers and a summary, studies topics in the theory of stochastic processes related to long-range dependence. Much recent interest in such probabilistic models has its origin in measurements of Internet traffic data, where typical characteristics of long memory have been observed. LÄS MER

  3. 2. On vortex breakdown in swirling annular jets

    Författare :Carl Fredrik Stein; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; swirling jets; vortex breakdown; conical self-similarity; swirl numbers; CFD; CFD;

    Sammanfattning : .... LÄS MER

  4. 3. Some Mathematical Aspects of Thermo and Fluid Dynamics

    Författare :Carl Fredrik Stein; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; swirling jets; vortex breakdown; conical self-similarity; Long s jet; Taylor s hypothesis; frozen turbulence hypothesis; advection velocity; conjugate heat transfer; asymptotic analysis; swirling jets;

    Sammanfattning : This thesis contains mathematical treatments of three issues in thermo and fluid dynamics: swirling jets and vortex breakdown, Taylor's hypothesis and conjugate heat transfer. The work on swirling jets is focused on the study of the well-posedness of the conically self-similar free-vortex solutions to the Navier--Stokes equations. LÄS MER

  5. 4. Injection and Combustion of Alternative Fuels in Spark Ignited Direct Injection Engines

    Författare :Lars Christian Riis Johansen; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gas fuel; direct injection; E85; stratified combustion; spark ignition; alternative fuels; optical measurements;

    Sammanfattning : Increasingly stringent vehicle emission legislation necessitates increasingly efficient combustion engines. The use of direct injection in spark ignited engines improves engine efficiency and reduces CO2 emissions. LÄS MER

  7. 5. A study of turbulence and scalar mixing in a wall-jet using direct numerical simulation

    Författare :Daniel Ahlman; Arne V. Johansson; Lars-Erik Eriksson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningmekanik; Fluid mechanics; Strömningsmekanik;

    Sammanfattning : Direct numerical simulation is used to study the dynamics and mixing in a turbulent plane wall-jet. The investigation is undertaken in order to extend the knowledge base of the influence of the wall on turbulent dynamics and mixing. The mixing statistics produced can also be used to evaluate and develop models for mixing and combustion. LÄS MER