Sökning: "Reynolds stress model"

Visar resultat 1 - 5 av 50 avhandlingar innehållade orden Reynolds stress model.

  1. 1. Modelling of stably-stratified, convective and transitional atmospheric boundary layers using the explicit algebraic Reynolds-stress model

    Författare :Velibor Zeli; Gert Brethouwer; Arne V. Johansson; Stefan Wallin; Bert Holtslag; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atmospheric turbulence; convective atmosphere; Reynolds-stress model; stably-stratified atmosphere; transitional atmosphere; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : The atmospheric boundary layer (ABL) is in continuous turbulent motion. The heating and cooling of the Earth’s surface drives mechanic and thermodynamic processes in the ABL through enhancing and damping of atmospheric turbulence. The surface forcing has a profound effect on the diurnal cycle of temperature,wind and related variables in the ABL. LÄS MER

  3. 2. On Turbulence Modelling for Bilge Vortices: A Test of Eight Models for Three Cases

    Författare :Urban Svennberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wake; turbulence modelling; nonlinear eddy-viscosity model; bilge vortices; ship flow; jet; Navier-Stokes equation; two-equation model; Reynolds stress model; vortex;

    Sammanfattning : This work is a test, in three steps, of turbulence models for the calculation of the flow field around ships. Eight models ranging from k-e and k-w models to a Reynolds-stress model (RSM) are tested. LÄS MER

  4. 3. Turbine Outlet Guide Vane Flows

    Författare :Johan Hjärne; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spalart-Allmaras model; k-ω SST model; linear cascade; secondary flows; turbine exhaust casing; RSM; k-ε realizable model; turbine rear frame; engine mount bump; tail bearing housing; Outlet guide vane;

    Sammanfattning : New design goals on modern jet engines often leads to more highly loaded turbines with fewer stages in order to save weight and cost. This gives higher swirl angles into the outlet guide vane (OGV), implying a more difficult aerodynamic design. LÄS MER

  5. 4. Turbulence Modelling and Parallel Solver Development Relevant for Investigation of Gas Turbine Cooling Processes

    Författare :Rongguang Jia; Värmeöverföring; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Thermal engineering; applied thermodynamics; Termisk teknik; termodynamik; large eddy simulation; Reynolds stress transport model; turbulence modelling; multi-block; parallel computing; Impingement cooling; ribbed surface;

    Sammanfattning : To enhance the performance of gas turbine engines, high top-cycle temperatures are desired. However, the temperature is limited by current materials. LÄS MER

  7. 5. Computational fluid-dynamics investigations of vortex generators for flow-separation control

    Författare :Florian von Stillfried; Arne Johansson; Stefan Wallin; Jonathan Morrison; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow-separation control; vane vortex generator; vortex generator jet; zero-pressure-gradient turbulent boundary layer; adverse-pressure-gradient turbulent boundary layer; statistical modelling; turbulence; Reynolds stress- transport model; computational fluid dynamics;

    Sammanfattning : Many flow cases in fluid dynamics face undesirable flow separation due to ad-verse pressure gradients on wall boundaries. This occurs, for example, due togeometrical reasons as in a highly curved turbine-inlet duct or on flow-controlsurfaces such as wing trailing-edge flaps within a certain angle-of-attack range. LÄS MER