Effects of roof configuration on natural ventilation for an isolated building
DOI:
https://doi.org/10.15282/jmes.15.3.2021.15.0659Keywords:
natural ventilation, roof configuration, computational fluid dynamics, steady RANS, ventilation rateAbstract
Numerical analyses based on CFD steady RANS were conducted to investigate the effects of roof configuration on wind-induced natural ventilation for an isolated roofed building. Gable roof and saltbox roof building models were tested with 15˚, 25˚, 35˚ and 45˚ roof pitch in present study. The flow field information and flow characteristics were obtained from the contours and plots generated by CFD. In accordance to the increment of roof pitch, the turbulence kinetic energy and mean velocity ratio show vigorous response. The flow separated at the windward corner do not reattach onto the roof, thus induced higher velocity gradient and form a large vortex at the roof ridge. The vortices behind then building caused by the flow separation at the roof ridge extend along the mixing layer and spread up to the roof. The pressure differences mainly rely on the roof shapes. Greater pressure differences between the upstream, interior and downstream was observed in saltbox roof cases. This is due to the extended roof height which boosted the impinging effect caused by the incoming wind. Generally, the saltbox roof configuration exhibit better performance than gable roof in terms of the measured parameters.
References
Department of Standards Malaysia, “MS1525–2014 Code of practice on energy efficiency and use of renewable energy for non residential buildings (2nd Revision)” 2014.
J. Kindangen, G. Krauss, and P. Depecker, “Effects of roof shapes on wind-induced air motion inside buildings,” Building and Environment, vol. 32, no. 1, pp. 1–11, 1997.
M. Mahdavinejad and K. Javanroodi, “Impact of roof shape on air pressure, wind flow and indoor temperature of residential buildings,” International Journal of Sustainable Building Technology and Urban Development, vol. 7, no. 2, pp. 87–103, 2016.
Y. L. Xu and G. F. Reardon, “Variations of wind pressure on hip roofs with roof pitch,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 73, no. 3, pp. 267–284, 1998.
R. Ramponi and B. Blocken, “CFD simulation of cross-ventilation for a generic isolated building: Impact of computational parameters,” Building and Environment, vol. 53, pp. 34–48, 2012.
L. K. Moey, N. M. Adam, and K. A. Ahmad, “Effect of venturi-shaped roof angle on air change rate of a stairwell in tropical climate,” Journal of Mechanical Engineering, vol. 4, no. 4, pp. 135–150, 2017.
Y. Tominaga, S. Akabayashi, T. Kitahara, and Y. Arinami, “Air flow around isolated gable-roof buildings with different roof pitches: Wind tunnel experiments and CFD simulations,” Building and Environment, vol. 84, pp. 204–213, 2015.
X. Zhou, Y. Zhang, L. Kang, and M. Gu, “CFD simulation of snow redistribution on gable roofs: Impact of roof slope,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 185, pp. 16–32, 2019.
M. G. Badas, S. Ferrari, M. Garau, and G. Querzoli, “On the effect of gable roof on natural ventilation in two-dimensional urban canyons,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 162, pp. 24–34, 2017.
P. Karava, T. Stathopoulos, and A. K. Athienitis, “Airflow assessment in cross-ventilated buildings with operable façade elements,” Building and Environment, vol. 46, no. 1, pp. 266–279, 2011.
J. Franke, A. Hellsten, H. Schlunzen, and B. Carissimo, “Best practice guideline for the CFD simulation of flows in the urban environment, ” ISBN 3-00-018312-4, 2007.
Y. Tominaga, A. Mochida, R. Yoshie, H. Kataoka, T. Nozu, M. Yoshikawa, and T. Shirasawa, “AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings,” Journal of Wind Engineering and Industrial Aerodynamics, vol. 96, pp. 1749–1761, 2008.
K. Zore, G. Parkhi, B. Sasanapuri, A. Varghese, “Ansys mosaic poly-hexcore mesh for high-lift aircraft configuration,” 21th Annual CFD Symposium, pp. 1–11, 2019.
B. E. Launder and D. B. Spalding, “The numerical computation of turbulent flows,” Numerical Prediction of Flow, Heat Transfer, Turbulence and Combustion, pp. 96-116, 1983.
B. Blocken, T. van Hooff, L. Aanen, and B. Bronsema, “Computational analysis of the performance of a venturi-shaped roof for natural ventilation: Venturi-effect versus wind-blocking effect,” Computers & Fluids, vol. 48, no. 1, pp. 202–213, 2011.
Y. Ozmen, E. Baydar, and J. P. A. J. van Beeck, “Wind flow over the low-rise building models with gabled roofs having different pitch angles,” Building and Environment, vol. 95, pp. 63–74, 2016.
S. Hawendi and S. Gao, “Impact of windward inlet-opening positions on fluctuation characteristics of wind-driven natural cross ventilation in an isolated house using LES,” International Journal of Ventilation, vol. 17, no. 2, pp. 93–119, 2018.
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