&lt;b&gt;Evaluation of CFD simulations with wind tunnel experiments: pressure coefficients at openings in sawtooth building

Marieli Azoia Lukiantchuki,Fernando Marques Da Silva,Rosana Maria Caram,Alessandra Prata Shimomura

doi:10.4025/actascitechnol.v40i1.37537

Abstract

Wind tunnel experiments and Computational Fluid Dynamics (CFD) simulations are used to analyze natural ventilation in a sawtooth roof building. A 1:10 scale model is tested in an atmospheric boundary layer wind tunnel. The CFD simulations are performed with Ansys CFX software. The aim of this study is to evaluate the reliability of CFD simulation in predicting pressure data at opening height in a sawtooth roof building with wind tunnel data. The model is evaluated for prevailing wind in five directions: 0 and 45° (air extractor sheds), 90° (neutral situation) and 135 and 180° (air collector sheds). The computational grid resolution shows that the inclusion of prisms and the increase of the grid refinement in the building’s surface cause insignificant differences in Cp (wind pressure coefficient). In general, the error values below 10% indicate a good agreement between CFD simulations and wind tunnel data.

Highlights

Natural ventilation is one of the most important passive cooling strategies to provide thermal comfort and healthier indoor environment in buildings
As in most of Brazilian territory, the use of natural ventilation can be an efficient strategy for the thermal comfort without the use of mechanical cooling (Cândido, De Dear, Lamberts, & Bittencourt, 2010)
Natural ventilation strategies can be explored in two ways, in order to minimize this problem: 1) through the stack effect, only dependent on indoor-outdoor temperature difference and an effective height difference between inlet and outlet openings, and 2) through the use of wind captors with openings above rooftops such as solar chimneys (Chen et al, 2003; Maerefat & Haghighi, 2010; Shi et al, 2016), wind towers

Summary

Introduction

Natural ventilation is one of the most important passive cooling strategies to provide thermal comfort and healthier indoor environment in buildings It minimizes energy consumption and environmental impacts, since the need for mechanical ventilation and air conditioning systems is reduced. As in most of Brazilian territory, the use of natural ventilation can be an efficient strategy for the thermal comfort without the use of mechanical cooling (Cândido, De Dear, Lamberts, & Bittencourt, 2010). This strategy is less efficient in areas with infrequent and weak winds, or inadequate spaces for air circulation within the urban network.

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