Sökning: "boundary layer"

Visar resultat 11 - 15 av 472 avhandlingar innehållade orden boundary layer.

  1. 11. Boundary Estimates for Solutions to Parabolic Equations

    Författare :Olow Sande; Kaj Nyström; Maciej Klimek; Juha Kinnunen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Uniformly parabolic equations; non-linear parabolic equations; linear growth; degenerate parabolic equations; fractional heat equations; complex coefficients; Lipschitz domain; NTA domain; boundary behaviour; boundary Harnack; parabolic measure; Riesz measure; Dirichlet to Neumann map; single layer potentials.; Mathematics; Matematik;

    Sammanfattning : This thesis concerns the boundary behavior of solutions to parabolic equations. It consists of a comprehensive summary and four scientific papers. The equations concerned are different generalizations of the heat equation.Paper I concerns the solutions to non-linear parabolic equations with linear growth. LÄS MER

  3. 12. Boundary layer streaks as a novel laminar flow control method

    Författare :Sohrab Sattarzadeh Shirvan; Jens H. M. Fransson; Edward B. White; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer stability; laminar to turbulent transition; laminar flow control; drag reduction; Tollmien-Schlichting waves; oblique waves; streaky boundary layers; miniature vortex generators; discrete suction;

    Sammanfattning : A novel laminar flow control based on generation of spanwise mean velocity gradients (SVG) in a flat plate boundary layer is investigated where disturbances of different types are introduced in the wall-bounded shear layer. The experimental investigations are aimed at; (i) generating stable and steady streamwise streaks in the boundary layer which set up spanwise gradients in the mean flow, and (ii) attenuating disturbance energy growth in the streaky boundary layers and hence delaying the onset of turbulence transition. LÄS MER

  4. 13. Direct numerical simulations of the rotating-disk boundary-layer flow

    Författare :Ellinor Appelquist; Philipp Schlatter; Henrik Alfredsson; Rebecca Lingwood; Christopher Davies; KTH; []
    Nyckelord :Fluid mechanics; boundary layer; rotating disk; laminar-turbulent transition; convective instability; absolute instability; secondary instability; crossflow instability; direct numerical simulations; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : This thesis deals with the instabilities of the incompressible boundary-layer flow that is induced by a disk rotating in otherwise still fluid. The results presented are mostly limited to linear instabilities derived from direct numerical simulations (DNS) but with the objective that further work will focus on the nonlinear regime, providing greater insights into the transition route to turbulence. LÄS MER

  5. 14. Modelling of boundary layer stability

    Författare :Paul Andersson; KTH; []
    Nyckelord :;

    Sammanfattning : .... LÄS MER

  7. 15. Boundary Layer Parametrization in Numerical Weather Prediction Models

    Författare :Jacob Svensson; Gunilla Svensson; Michael Tjernström; Patrick Samuelsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Boundary-Layer Meteorology; Numerical Weather Prediction; Turbulence parametrization; COAMPS; IFS; meteorologi; Meteorology;

    Sammanfattning : Numerical weather prediction (NWP) and climate models have shown to have a challenge to correctly simulate stable boundary layers and diurnal cycles. This aim of this study is to evaluate, describe and give suggestions for improvements of the descriptions of stable boundary layers in operational NWP models. Two papers are included. LÄS MER