3D LES simulation of the wind induced loads and pressures around a 3:2 ratio rectangular prism at different angles of attack

Antonio J. Álvarez , Félix Nieto , Kenny C. S. Kwok , Luca Patruno

Abstract

The ratio 3:2 rectangular prism belongs to the separated type flow at 0° angle of attack (AOA), featuring a critical AOA in the range (8°, 9°), in smooth flow, for which important changes in the force coefficients and flow patterns have been described, based on experimental tests. 3 LES simulations are presented herein for 0°, 4°, 8° and 12° AOA in smooth flow, aiming at i) shedding additional light on the flow features and wind-induced actions before and after the critical AOA, and ii) assessing the ability of 3D LES models to correctly simulate the aerodynamic behaviour of this geometry, which has been categorized as Reynolds number sensitive, showing some non-Gaussian characteristics according to recent experimental research. The CFD simulations were successful in capturing the changes in the mean force coefficients for the studied angles of attack. Similarly, mean and extreme pressure coefficients were obtained, showing the CFD-based pressure distributions minor bias in the median towards higher values, when compared with wind tunnel data. Furthermore, mean flow structures and pressure correlations distributions have been analysed, providing an enhanced description of the flow features at AOA lower and higher than the critical one.

Key Words

3:2 prism; 3D LES; correlation; force coefficients; friction coefficient; pressure distributions; streamlines

Address

Antonio J. Álvarez — CITEEC, University of A Coruña, A Coruña, Galicia, Spain
Félix Nieto — CITEEC, University of A Coruña, A Coruña, Galicia, Spain
Kenny C. S. Kwok — The University of Sydney, Sydney, Australia
Luca Patruno — University of Bologna, Bologna, Italy

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