Sökning: "unsteady"

Visar resultat 11 - 15 av 176 avhandlingar innehållade ordet unsteady.

1. 11. Modeling of Unsteady Flow Effects in Throughflow Calculations

   Författare :Magnus Stridh; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; rotor-stator interaction; mixing-plane; linear Navier-Stokes; cascade; turbomachinery; transport equation; Linear harmonic; compressor; throughflow; turbine; Deterministic stress terms;

   Sammanfattning : In this work an evaluation of a deterministic stress transport model and a linearized Navier-Stokes harmonic approach for including unsteady effects in the steady mixing-plane computations of a multistage transonic compressor has been performed. The results of these two models are compared with those of time-average time-accurate solutions. LÄS MER

3. 12. On Rail Vehicle Dynamics in Unsteady Crosswind Conditions : Studies Related to Modelling, Model Validation and Active Suspension

   Författare :Dirk Thomas; Berg Mats; Sebastian Stichel; Jordi Vinolas; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Järnvägsgruppen - Fordonsteknik; Järnvägsgruppen - Fordonsteknik;

   Sammanfattning : Crosswind stability of rail vehicles has been a research area for several decades, mainlymotivated by vehicle overturning accidents and higher speeds, but in recent times also byissues of lower energy consumption and track maintenance costs demanding lower vehi-cle weights. During everyday operation, rail vehicles are subjected to substantial lateralinfluences from track curves, track irregularities and crosswind, leading to large suspen-sion deflections and increased crosswind sensitivity. LÄS MER

4. 13. Aerodynamics simulations of ground vehicles in unsteady crosswind

   Författare :Tristan Favre; Gunilla Efraimsson; Michael Leschziner; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Detached-Eddy Simulations; Crosswind; Aerodynamics; ;

   Sammanfattning : Ground vehicles, both on roads or on rail, are sensitive to crosswinds and the handling, travelling speeds or in some cases, safety can be affected. Full modelling of the crosswind stability of a vehicle is a demanding task as the nature of the disturbance, the wind gust, is complex and the aerodynamics, vehicle dynamics and driver reactions interact with each other. LÄS MER

5. 14. Numerical Simulation of Unsteady Flows of Physiological Relevance

   Författare :Philip Evegren; Institutionen för energivetenskaper; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wall shear stress; Biofluid mechanics; Pulsatile flow; Atherosclerosis; Flow in bifurcations;

   Sammanfattning : Pulsatile flows in geometries of physiological relevance have been investigated. Atherosclerotic plaques are (initiated) near junctions and bifurcations in larger arteries. The flow in these regions is characterized by flow separation and unsteadiness, which indicates that local flow conditions contribute to atherogenesis. LÄS MER

7. 15. Lateral Stability of High-Speed Trains at Unsteady Crosswind

   Författare :Dirk Thomas; Mats Berg; Sebastian Stichel; Carsten Bussmann; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vehicle engineering; Farkostteknik;

   Sammanfattning : Crosswind stability of rail vehicles has been a research area for several decades,mainly motivated by vehicle overturning accidents and higher speeds, but in recenttimes also by issues of lower energy consumption and track maintenance costsdemanding lower vehicle weights. During everyday operation, rail vehicles are subjectedto large lateral influences from track irregularities, track curves and crosswind,leading to large suspension deflections and increased crosswind sensitivity. LÄS MER