Search for dissertations about: "LES"

Showing result 11 - 15 of 250 swedish dissertations containing the word LES.

  2. 11. Turbulence-resolving Simulations of Swirling Flows

    Author : Ardalan Javadi; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Swirling Flow; URANS; Hydropower; Hybrid URANS-LES; SAS; Flow Control; Turbulence Modeling; Vortex Breakdown; DDES; LES;

    Abstract : A series of numerical investigations is undertaken using a wide range of turbulence mod-els including conventional and non-conventional URANS models, hybrid URANS-LESmethods and LES to capture a large variety of physical mechanisms that produce pres-sure pulsations in the swirling flows. The available knowledge about these pulsations,which are usual in hydropower, are still far from complete. READ MORE

  4. 12. Numerical Simulation of High Reynolds Number Wall Bounded Flow

    Author : Tobias Persson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; subgrid model; DES; high; validation; LES; numerical simulation; near-wall;

    Abstract : In this thesis, four different numerical methods are used for predictions of high Reynoldsnumber (Re), wall bounded flows; Large Eddy Simulation (LES) with two different subgrid(turbulence) models, the One Equation Eddy Viscosity model (OEEVM) and the MixedModel (MM), Monotone Integrated LES (MILES), Detached Eddy Simulation (DES) andReynolds Averaged Navier Stokes (RANS). The LES calculations are combined with a wallmodel based on the law-of-the-wall and in DES a hybrid RANS/LES method is used forhandling the near wall region. READ MORE

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

    Author : Sinisa Krajnovic; Chalmers tekniska högskola; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 14. Large Eddy Simulation of Turbulent Flow and Combustion in HCCI Engines

    Author : Rixin Yu; Strömningsteknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent combustion; Numerical methods.; LES; Temperature inhomogeneity; HCCI combustion; In-cylinder flow;

    Abstract : This thesis deals with numerical simulations of the turbulent combustion process in Homogeneous Charge Compression Ignition (HCCI) engines. An accurate and computationally efficient Large Eddy Simulation (LES) model was developed and used throughout this thesis to investigate the development of in-cylinder turbulence, temperature stratification, onset of auto-ignition, and development of the reaction fronts. READ MORE

  7. 15. Drag reduction using plasma actuators

    Author : Romain Futrzynski; Gunilla Efraimsson; P. Henrik Alfredsson; Charles Mockett; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; drag reduction; plasma actuator; DMD; LES; optimization; pulsating flow; strömningskontroll; motståndsminskning; plasma ställdon; DMD; LES; optimering; pulserande flöde; Engineering Mechanics; Teknisk mekanik;

    Abstract : This thesis is motivated by the application of active flow control on the cabin of trucks, thereby providing a new means of drag reduction. Particularly, the work presented strives to identify how plasma actuators can be used to reduce the drag caused by the detachment of the flow around the A-pillars. READ MORE