Sökning: "neutral boundary layer"

Visar resultat 1 - 5 av 14 uppsatser innehållade orden neutral boundary layer.

  1. 1. Verification and validation of the implementation of an Algebraic Reynolds-Stress Model for stratified boundary layers

    Master-uppsats, KTH/Teknisk mekanik

    Författare :Martina Formichetti; [2022]
    Nyckelord :Atmospheric boundary layer; turbulence modelling; stratified flows; eddy viscosity; eddy diffusivity;

    Sammanfattning : This thesis studies the implementation of an Explicit Algebraic Reynolds-Stress Model(EARSM) for Atmospheric Boundary Layer (ABL) in an open source ComputationalFluid Dynamics (CFD) software, OpenFOAM, following the guidance provided by thewind company ENERCON that aims to make use of this novel model to improvesites’ wind-field predictions. After carefully implementing the model in OpenFOAM,the EARSM implementation is verified and validated by testing it with a stratifiedCouette flow case. LÄS MER

  3. 2. Evaluation of a stochastic model of coherent turbulent structures for atmospheric particle deposition applications

    Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Andreas Eriksson; [2022]
    Nyckelord :atmospheric dispersion; particle deposition; k-epsilon; RANS; lagrangian particle model; stochastic particle model; OpenFOAM; SIMPLE algorithm; ABL; atmospheric boundary layer; neutral boundary layer; coherent turbulent structures;

    Sammanfattning : In this thesis, we have evaluated a stochastic Lagrangian model for computing particle deposition rates with prospects to use for atmospheric deposition applications.  The model is one-dimensional and models the particle dynamics in the boundary layers near walls and obstacles by simulating the coherent turbulent structures and Brownian motion governing the wall-normal transport. LÄS MER

  4. 3. Cloud Streets. A Study of the Instability Mechanisms Giving Rise to Boundary Layer Rolls

    Master-uppsats, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Josefine Bergstedt; [2020]
    Nyckelord :Cloud streets; boundary layer rolls; dynamic instability; thermal instability; horizontal con- vective rolls; inflection point;

    Sammanfattning : Boundary layer rolls are a rather frequent phenomena, where regions of alternating up- and downdraft motion causes clouds to form in elongated, parallel rows oriented with the mean wind direction. The clouds can be seen during certain atmospheric conditions and are often called ”cloud streets” because of their characteristic appearance. LÄS MER

  5. 4. Cloud Observations at a Coastal site – Analysis of Ceilometer Measurements from Östergarnsholm, Sweden

    Master-uppsats, Uppsala universitet/Luft-, vatten- och landskapslära

    Författare :Aron Stenlid; [2019]
    Nyckelord :Ceilometer; Stratocumulus; cloud base height; LCL; DLS; upwelling; cloud cover;

    Sammanfattning : In this study, four and a half months of ceilometer data from Östergarnsholm are used to analyze cloud related to processes in the boundary layer. Measurements are divided into two categories, which are defined by wind direction: a continental and a marine sector. LÄS MER

  7. 5. Analysis and control of boundary layer transition on a NACA 0008 wing profile

    Master-uppsats, KTH/Mekanik

    Författare :Arijit Sinha Roy; [2018]
    Nyckelord :boundary layer stability; laminar - turbulent transition; laminar flow control; Tollmien-Schlichting waves; streaky boundary layers; miniature vortex generators; Falkner-Skan boundary layer.;

    Sammanfattning : The main aim of this thesis was to understand the mechanism behind the classical transition scenario inside the boundary layer over an airfoil and eventually attempting to control this transition utilizing passive devices for transition delay. The initial objective of analyzing the transition phenomenon based on TS wave disturbance growth was conducted at 90 Hz using LDV and CTA measurement techniques at two different angles of attack. LÄS MER