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Visar resultat 1 - 5 av 176 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Modeling Unsteady flow Effects in 3D Throughflow Calculations

   Författare :Magnus Stridh; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; throughflow; turbomachinery; mixing-plane; rotor-stator interaction; cascade; Deterministic stress terms; Linear harmonic; compressor; preconditioned GMRES; Unsteady; linear Navier-Stokes; turbine;

   Sammanfattning : The flow field in a transonic multistage compressor is compressible, three-dimensional and highly unsteady and can be predicted in principle by the exact time-accurate Navier-Stokes equations. The high Reynolds number encountered in multistage turbomachinery together with the wall-bounded nature of the flow environment however prevent the use of DNS to solve the exact N-S equations. LÄS MER

3. 2. Unsteady Navier Stokes solver for the simulation of compressor flutter in turbomachines

   Författare :L. D. Gunnar Sidén; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; finite volume; finite element; compressor; fan; flutter; Navier Stokes; turbo machinery; unsteady; time marching;

   Sammanfattning : .... LÄS MER

4. 3. Numerical Investigation of Unsteady Crosswind Aerodynamics for Ground Vehicles

   Författare :Tristan Favre; Gunilla Efraimsson; Mattias Chevalier; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aerodynamics; Vehicle Aerodynamics; Unsteady Aerodynamics; Crosswind; Unsteady Crosswind Aerodynamics; Detached-Eddy Simulations; DES; Vehicle engineering; Farkostteknik; Fluid mechanics; Strömningsmekanik;

   Sammanfattning : Ground vehicles are subjected to crosswind from various origins such as weather, topography of the ambient environment (land, forest, tunnels, high bushes...) or surrounding traffic. LÄS MER

5. 4. On Multistage Analysis of Transonic Compressors: From Axisymmetric Throughflow Time-Marching to Unsteady Three-Dimensional Methods

   Författare :Stephane Baralon; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; shock; time-marching; deterministic; average-passage; multistage; fan; axisymmetric; 3D; unsteady; transonic; viscous; body force; stress; singularity; perturbation; throughflow; mixing-plane; modelling; finite-volume;

   Sammanfattning : A throughflow time-marching finite-volume solver, capable of computing viscous transonic multistage compressor flows with embedded shocks, is presented. The behavior of the blade model, based on the blade mean surface flow tangency condition, was investigated for transonic flows. LÄS MER

7. 5. Realistic simulations of delta wing aerodynamics using novel CFD methods

   Författare :Stefan Görtz; Arthur Rizzi; Miguel Visbal; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; CFD; aerodynamics; flow physics; steady; unsteady; delta wing; vortical flow; Rymd- och plasmafysik; Space physics; Rymdfysik;

   Sammanfattning : The overall goal of the research presented in this thesis is to extend the physical understanding of the unsteady external aerodynamics associated with highly maneuverable delta-wing aircraft by using and developing novel, more efficient computational fluid dynamics (CFD) tools. More specific, the main purpose is to simulate and better understand the basic fluid phenomena, such as vortex breakdown, that limit the performance of delta-wing aircraft. LÄS MER