Sökning: "Implicit LES"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden Implicit LES.

1. 1. Transonic flow: large eddy simulation, numerical methods and subgrid modeling

   Författare :Christian Wollblad; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; SGS modeling; Transonic flow; semi-implicit numerical scheme; shock wave turbulent boundary layer interaction;

   Sammanfattning : Shock wave turbulent boundary layer interactions (SWTBLI) commonly arise in turbomachinery and aerospace applications and on the exterior of high speed aircrafts. In all these cases, SWTBLI can significantly change the flow and hence the physical load imposed by it. 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. 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

5. 4. Adaptive Algorithms and High Order Stabilization for Finite Element Computation of Turbulent Compressible Flow

   Författare :Murtazo Nazarov; Johan Hoffman; Timothy J. Barth; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Compressible flow; adaptivity; finite element method; a posteriori error estimates; Implicit LES; Applied mathematics; Tillämpad matematik; Numerical analysis; Numerisk analys;

   Sammanfattning : This work develops finite element methods with high order stabilization, and robust and efficient adaptive algorithms for Large Eddy Simulation of turbulent compressible flows. The equations are approximated by continuous piecewise linear functions in space, and the time discretization is done in implicit/explicit fashion: the second order Crank-Nicholson method and third/fourth order explicit Runge-Kutta methods. LÄS MER

7. 5. Numerical Study of Laminar, Transitional and Turbulent Flow Past Rectangular Cylinders

   Författare :Ahmad Sohankar Esfahani; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; blockage; outlet boundary condition; rectangular cylinders; onset of vortex shedding; angle of incidence; incompressible flow; LES; DNS; transition; finite volumes; Reynolds number; numerical simulation; square cylinder;

   Sammanfattning : The subject of flow past slender bluff bodies is of relevance to technical problems associated with energy conservation, structural design and acoustic emissions. The present work is restricted to an important sub-class of slender bluff body flow --- the incompressible flow around a stationary cylinder having a rectangular cross section, the cylinder being exposed to a constant free stream velocity. LÄS MER