Sökning: "Large Eddy Simulations LES"

Visar resultat 1 - 5 av 100 avhandlingar innehållade orden Large Eddy Simulations LES.

1. 1. Methodologies for RANS-LES interfaces in turbulence-resolving simulations

   Författare :Sebastian Arvidson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; zonal RANS-LES; aeronautics; RANS-LES interfaces; Hybrid RANS-LES; grey-area mitigation; log-layer mismatch; embedded LES; LES length scale; LES;

   Sammanfattning : Hybrid Reynolds-Average Navier-Stokes (RANS)-Large-Eddy Simulations (LES) techniques are now seen by the aeronautical industry as the most promising turbulence-resolving approaches for complex high-Reynolds-number turbulent flows with regard to cost and accuracy. However, connecting RANS and LES simulated flows is a challenging task and needs special attention in order to increase simulation robustness and accuracy. LÄS MER

3. 2. Large Eddy Simulations of Separated Compressible Flows around Wing Sections

   Författare :Jörgen Held; Strömningsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; turbulence; subgrid-scale; shock-boundary layer interaction; wing section; transonic; subsonic; compressible; separated; Large eddy simulation; LES; PVM; Mechanical engineering; hydraulics; vacuum technology; vibration and acoustic engineering; Maskinteknik; hydraulik; vakuumteknik; vibrationer; akustik;

   Sammanfattning : This thesis concerns numerical calculations of compressible separated flows, with and without shocks, around wing sections using Large Eddy Simulations (LES). The considered geometries are the NACA 0012 wing section and the ONERA AT15A wing section. LÄS MER

4. 3. Creation and destruction of in-cylinder flows : Large eddy simulations of the intake and the compression strokes

   Författare :Martin Söder; Laszlo Fuchs; Angelo Onorati; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Swirl; Tumble; Compression; Engine; LES; CFD; engine turbulence; engine simulations; intake flow structures; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : The aim of this thesis is to increase engine efficiency by studying the flow structures created in an engine cylinder during the intake phase and the effect of the subsequent compression.The invention of the combustion engine has enabled three centuries of economic growth fueled by energy stored as hydrocarbons. LÄS MER

5. 4. Large-Eddy Simulation for Computing the Flow Around Vehicles

   Författare :Sinisa Krajnovic; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; LES; Subgrid scale model; Bus; SGS model; Car; Vehicle; Large eddy simulation;

   Sammanfattning : The feasibility of the use of large-eddy simulation (LES) in external vehicle aerodynamics is investigated. The computational requirement for LES of the full size car at road conditions is beyond the capability of computers in the near future. Since LES cannot be used for quantitative prediction of this flow, i.e. LÄS MER

7. 5. Large Eddy Simulation of Turbulent Flows in Combustor Related Geometries

   Författare :Jessica Gullbrand; Institutionen för energivetenskaper; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Mechanical engineering; Energiforskning; Energy research; Cartesian grid; high order wall treatment; SGS models; turbulence; subgrid scale models; LES; Large Eddy Simulation; akustik; vibrationer; vakuumteknik; hydraulik; vibration and acoustic engineering; Maskinteknik; vacuum technology; hydraulics;

   Sammanfattning : Numerical simulations using Large Eddy Simulation (LES) are applied to turbulent swirling flow fields. The swirling motion is often introduced into combustors to act as flame holders or enhance the mixing between species. Different turbulence models capture the swirling motion more or less accurately. LÄS MER