Numerical determination of drag coefficient for guyed mast exposed to wind action

Abstract

Guyed masts are used for meteorological measurements, in the telecommunication industry for wireless communication or for power transmission. For a guyed mast, wind load is the main factor affecting the stability of the structure. Determination of drag coefficient for lattice structure has been investigate in past. ESDU 81027 and 81028 and Eurocode 3 Part 3.1 give already some detailed information of the aerodynamic drag coefficient of lattice mast structures with circular members. Only certain types of lattice masts covers literature and codes tend to be conservative due to the necessity of simplicity. But in this study is presented numerical method using Computational Fluid Dynamics (CFD) to determine drag coefficient. The motivation for this study to investigate what CFD can offer or contribute to determine the aerodynamic drag forces of lattice mast structures as a supplement or even alternative to literature and codes. This would be in particular of interest for design engineers in the field of mast structures. Three-dimensional numerical simulations of one segment of a mast exposed to a wind action with three models of turbulence are performed. Three models of turbulence: standard k-epsilon model, RNG k-epsilon model and Reynolds stress model were used and compared with available experimental results. Drag coefficient was calculated based on integration surface pressure distribution, flow field and a reference area. Modeling was performed for four wind velocities, 10 m/s, 20 m/s, 30 m/s and 40 m/s. Reynolds number for those velocities corresponds to turbulence flow. Direction of inlet velocity is also variable, e.g. there are two angles of attack. (C) 2014 Elsevier Ltd. All rights reserved.