An investigation into the attenuation of wind speed by the use of windbreaks in the vicinity of overhead wires

Abstract

An experimental and computational analysis of the efficacy of windbreaks for the attenuation of wind speed in the vicinity of overhead wires is presented. This work has been specifically applied to the case of oscillation of overhead catenary contact wires in a cross-wind. A wind tunnel subscale model of a windbreak/overhead wire configuration is presented and discussed with regard to the feasibility of reducing the aerodynamically induced oscillations encountered in such situations. This porous blockage placed upstream of the simulated overhead wire attempts to represent the influence of a windbreak/shelterbelt on the reduction of the vibration phenomenon known as galloping. In conjunction with this experimental study, a computational fluid dynamics (CFD) analysis has been carried out in order to assess the influence of the shelterbelt on the catenary wires in a typical full-scale scenario. The results indicate that a dense shelterbelt of height H positioned between 2-8 tree heights, H, upstream of the suspended cables provides a sufficient reduction in wind speed to reduce significantly the amplitude of wire vibration.

Keywords

galloping wind tunnel shelterbelt windbreak trees CFD

Get full access to this article

View all access options for this article.

References

Sachs

Wind Forces in Engineering (Pergamon Press).

Caborn

J. M.

Shelterbelts and Windbreaks, 1965 (Faber and Faber).

Smith

A case study and analysis of the Tacoma Narrows bridge failure. Engineering Project 99.497, Department of Mechanical Engineering, Carleton University, Ottawa, Canada, 29 March 1974.

Simiu

Scanlan

R. H.

Wind Effects on Structures, 1996 (Wiley Interscience).

Bergström

Högström

Turbulent exchange above a pine forest II. Organised structures

Boundary Layer Meteorology, 1989, 49, 231–236.

Chen

Turbulent characteristics over a rough natural surface, Part I: Turbulent structures

Boundary Layer Meteorology, 1990, 52 151–175.

Shaw

R. H.

Schumann

Large eddy simulation of turbulent flow above and within a forest

Boundary Layer Meteorology, 1992, 61, 47–64.

Shen

Leclerc

M. Y.

Modelling the turbulence structure in the canopy layer

Agricultural and Forest Meteorology, 1997, 87, 3–25.

Launder

B. E.

Spalding

D. B.

The numerical computation of turbulent flows

Comput. Meth. in Appl. Mech. Engng, 1974, 3, 269–289.

10.

PHOENICS, 1999 (CHAM Limited, Wimbledon, UK).

11.

Patankar

S. V.

Numerical Heat Transfer and Fluid Flow, 1980 (Hemisphere, New York).

12.

Robins

A. G.

Castro

I. P.

A wind tunnel investigation of plume dispersion in the vicinity of a surface mounted cube-I. The flow field

Atmos. Environ., 1977, 11, 291–297.

13.

Scanlon

T. J.

A numerical analysis of flow and dispersion around a cube. Fifth International Conference of the International Building Performance Simulation Association, Prague, Czech Republic, 8-10 September 1997, Vol. 1, pp. 241–249.