Sökning: "radius model"

Visar resultat 21 - 25 av 143 avhandlingar innehållade orden radius model.

1. 21. Rail Corrugation Growth on Curves

   Författare :Peter Torstensson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; simulation; track and wheelset structural flexibility; small radius curves; short-pitch rail corrugation; dynamic vehicle–track interaction; test rig and field measurements; wear;

   Sammanfattning : Short-pitch rail corrugation that may develop on the low (inner) rail on small radius curves causes increased noise and vibration levels on railway networks worldwide. In lack of a generally applicable treatment, track authorities are forced to run expensive rail grinding programs on a regular basis to manage these problems. LÄS MER

3. 22. Continuum Percolation in non-Euclidean Spaces

   Författare :Johan Tykesson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bernoulli percolation; continuum percolation; dependent percolation; double phase transition; hyperbolic space; Poisson Boolean model; geodesic percolation; continuum percolation;

   Sammanfattning : In this thesis we first consider the Poisson Boolean model of continuum percolation in $n$-dimensional hyperbolic space ${\mathbb H}^n$. Let $R$ be the radius of the balls in the model, and $\lambda$ the intensity of the underlying Poisson process. LÄS MER

4. 23. LES stochastic modelling of cavitation with its applications in OpenFOAM

   Författare :Boxiong Chen; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rayleigh-Plesset Equation; Cavitation; Modelling; Simulation; Eulerian Stochastic Field Method; OpenFOAM; Homogeneous Equilibrium Model;

   Sammanfattning : Cavitation is a vaporization process that commonly happens in high-pressure injector nozzles nowadays. It has been shown by previous studies that cavitation has a significant influence on the subsequent atomization process, the quality of which would in turn heavily affect the process of combustion. LÄS MER

5. 24. Aerodynamic Design and Optimization of Intermediate Ducts for High By-pass Ratio Jet Engines

   Författare :Fredrik Wallin; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Intermediate transition ducts; vortex generators; S-shaped ducts; response surface methodology; source term model; optimization;

   Sammanfattning : Demands on improved efficiency and reduced noise levels cause a strive toward high by-pass ratio commercial aero engines. This results in multi-spool aero engines with small high-pressure ratio cores and large fans. The low-pressure system has a lower rotational speed and a larger radius than the high-pressure core system. LÄS MER

7. 25. Astrophysical and Collider Signatures of Extra Dimensions

   Författare :Henrik Melbéus; Tommy Ohlsson; Jörn Kersten; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Extra-dimensional quantum field theories; universal extra dimensions; Kaluza-Klein dark matter; Arkani-Hamed-Dimopoulos-Dvali model; hierarchy problem; neutrino mass; seesaw mechanism; Large Hadron Collider phenomenology; Elementary particle physics; Elementarpartikelfysik;

   Sammanfattning : In recent years, there has been a large interest in the subject of extra dimensions in particle physics. In particular, a number of models have been suggested which provide solutions to some of the problems with the current Standard Model of particle physics, and which could be tested in the next generation of high-energy experiments. LÄS MER