Determination of antenna specification and positioning for efficient railway communication in tunnels of arbitrary cross section

2011 ◽  
Author(s):  
Jorge Avella Castiblanco ◽  
Divitha Seetharamdoo ◽  
Marion Berbineau ◽  
Michel Ney ◽  
Francois Gallee
Keyword(s):  
Cross Section ◽  
Arbitrary Cross Section

Graphical-Numerical Solution of Problems of Saint-Venant Torsion and Bending

1953 ◽  
Vol 20 (3) ◽  
pp. 321-326
Author(s):  
B. A. Boley
Keyword(s):  
Cross Section ◽  
Stress Function ◽  
Arbitrary Cross Section ◽  
Successive Approximations ◽  
Shear Stresses ◽  
Shearing Stress ◽  
First Approximation ◽  
Difference Form ◽  
Bending Of Beams

Abstract A simple successive-approximations procedure for the solution of the problems of Saint-Venant torsion and bending of beams of arbitrary cross section is presented. The shear stresses in a cross section of the beam are first calculated from the formulas valid for thin-walled sections, on the basis of an assumed set of lines of shearing stress. From these a first approximation to the stress function of either the torsion or the bending problem is found. The second approximation to the stress function is then obtained from the governing equation of the problem, expressed in finite-difference form; this in turn allows the determination of an improved set of lines of shearing stress, and hence of the shearing stress itself. The procedure can be repeated until the results of two successive steps are sufficiently close. Applications are presented for a beam cross section for which the exact solutions are known, and it is shown that no further difficulties arise in applications to more complicated shapes.

Hydrodynamic Entrance Lengths for Ducts of Arbitrary Cross Section

1967 ◽  
Vol 89 (4) ◽  
pp. 847-850 ◽  
Author(s):  
S. T. McComas
Keyword(s):  
Velocity Profile ◽  
Detailed Analysis ◽  
Cross Section ◽  
Analytical Method ◽  
Arbitrary Cross Section ◽  
Numerical Results ◽  
Entrance Length ◽  
Flow Development

A general analytical method is presented for determination of the hydrodynamic entrance length of ducts of arbitrary cross section. Only knowledge of the fully developed velocity profile is required in order to determine this length in comparison to other approaches which require a detailed analysis of the flow development. This method is applied to circular, elliptical, annular, rectangular, and triangular ducts with numerical results presented.

A Method for the Determination of the Local Turbulent Friction Factor and Heat Transfer Coefficient in Generalized Geometries

1971 ◽  
Vol 93 (1) ◽  
pp. 61-68 ◽  
Author(s):  
E. Aranovitch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Laminar Flow ◽  
Transfer Coefficient ◽  
Cross Section ◽  
Arbitrary Cross Section ◽  
Transfer Coefficients ◽  
Turbulent Friction ◽  
Heat Transfer Coefficients

A method is presented for the determination of the distributions of velocity, local friction, and heat transfer coefficients in a forced axial turbulent flow with an arbitrary cross section. The method uses as basis the characteristics of the laminar flow. A comparison is made with some experimental results concerning different geometries.

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