The Eighth Asia-Pacific Conference on Wind Engineering, December 10–14, 2013, Chennai, India NUMERICAL ASSESSMENT OF AERODYNAMIC FORCES ON 2-D L-ANGLE SECTION USING CFD S. Chitra Ganapathi 1 , P. Harikrishna 2 and Nagesh R. Iyer 3 1 Scientist, CSIR-Structural Engineering Research Centre, Chennai, TN, India, chitrag@serc.res.in 2 Principal Scientist, CSIR-Structural Engineering Research Centre, Chennai, TN, India, hari@serc.res.in 3 Director, CSIR-Structural Engineering Research Centre, Chennai, TN, India, nriyer@serc.res.in ABSTRACT Numerical simulations of aerodynamic forces on regular shaped bluff-bodies using CFD have been well reported in the literature as part of validation. In the present study, CFD simulations have been carried out on a 2-D L- angle section using different Reynolds-Averaged Navier Stokes (RANS) based turbulence models to assess their performance in evaluating drag and lift coefficients for various angles of wind incidence. Mean drag and lift coefficients for the 2-D L-angle section have been evaluated under uniform smooth flow conditions using FLUENT 6.3 software. The performance of these turbulence models are assessed by comparing the numerically evaluated force coefficients of the 2-D L-angle section with the experimental results available in literature and also with the values provided in various international standards. SST k– model is observed to perform better in evaluating the above mentioned aerodynamic coefficients than other turbulence models, which are observed to perform better only in evaluating mean lift force coefficients than mean drag coefficients. Further, comparison of the numerically evaluated mean pressure coefficient distributions on various sides of the 2-D L-angle section have been made to discuss the relative performance and the limitations of the considered turbulence models. Keywords: CFD, L-angle section, Drag coefficient, Lift coefficient Introduction Most of the validation studies of CFD simulations reported in the literature correspond to regular shaped bluff bodies like square, rectangular, circular, etc. Recently, a benchmark study named as Benchmark on the Aerodynamics of a Rectangular 5:1 Cylinder (BARC) has been carried out by the International Association for Wind Engineering (IAWE). Very few numerical studies have been reported in the literature on irregular shaped structural sections. Besides, recent advancement in the field of telecommunication technology has resulted in many communication lattice towers. These lattice structures invariably use L-angle section as primary and secondary members because of ease of connections which have increased the demand on angle sections studies for the evaluation of wind loads as compared to other irregular shapes. Gomes et al. (2005) carried out CFD simulations on buildings with L and U plan shapes and compared the numerically evaluated pressure distributions with the wind tunnel results. Meroney et al. (1999) carried out numerical simulation of wind flow and dispersion of gases around buildings with irregular shapes by using standard k–ε, RNG k–ε, and Reynolds-stress turbulence models available in FLUENT software and good agreement was observed between numerically and experimentally obtained results for normal wind incidence. Leitl et al. (1997) used FLUENT for simulating the flow and dispersion of gases around a building with U- shaped plan view. The numerical results were compared with wind tunnel measurements. Stathopoulos and Zhou (1993) examined the wind loads for building with L-shaped plan view as well as for building with L-shaped elevation (stepped-roof) through numerical study. Proc. of the 8th Asia-Pacific Conference on Wind Engineering – Nagesh R. Iyer, Prem Krishna, S. Selvi Rajan and P. Harikrishna (eds) Copyright c  2013 APCWE-VIII. All rights reserved. Published by Research Publishing, Singapore. ISBN: 978-981-07-8011-1 doi:10.3850/978-981-07-8012-8 246 650