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Parametric study on wind pressure distribution of rural house by varying the roof overhang ratio and roof pitch

Parametric study on wind pressure distribution of rural house by varying the roof overhang ratio and roof pitch / Poon Jing Lin
Baru-baru ini, bencana angin ribut yang telah menyebabkan kerosakan bumbung rumah kampung sering dilaporkan dalam media massa. Kebanyakan kes ini berlaku di wilayah utara Semenanjung Malaysia. Banyak faktor yang menyumbang kepada kerosakan bumbung akibat tiupan angin. Antara faktor yang boleh menyebabkan bumbung rumah tersebut ditiup angin ialah unjur bumbung dan kecerunan bumbung rumah. Analisa Pengkomputeran Dinamik Bendalir yang terdapat pada ANSYS FLUENT 14 telah digunakan untuk simulasi numerikal dengan tujuan mengkaji pengaruh nisbah unjur bumbung dan kecerunan bumbung terhadap taburan tekanan angin dan corak aliran angin. Sebelum itu, satu kerja pengesahan telah dibuat berdasarkan keputusan dari kajian terdahulu dengan tujuan memastikan penggunaan data input dan arahan yang terkandung dalam ANSYS FLUENT 14 digunakan dengan tepat. Kerja pengesahan ini telah memberikan persamaan yang baik dengan model rujukan. Kajian sebenar telah memodelkan bangunan setingkat dan membezakan unjur bumbung serta kecerunan bumbung. Keputusan simulasi menunjukkan tekanan bersih adalah berkadar songsang terhadap magnitud unjur bumbung pada kebanyakan model. Bumbung dengan kecerunan 12° telah menghasilkan pekali tekanan negatif (sedutan) tertinggi pada unjur bumbung. Sebaliknya, pembentukan zon pengedaran semula dan lapisan bercampur adalah didapati hampir serupa bagi bumbung dengan kecerunan 27° dan 22°. Justeru itu dapatlah disimpulkan bahawa tekanan bersih (sedutan) yang lebih besar terhasil apabila sudut bumbung secara relatifnya rendah. Juga, corak larasan aliran dipengaruhi oleh nilai kecerunan bumbung tetapi bukan magnitud unjur bumbung. _______________________________________________________________________________________________________ Recently, roof damages disaster cases of non-engineered houses are widely reported in the mass media. Most of them happened in the northern region of peninsular of Malaysia. There are many factors that will influence the blown off of the roof. Among the factors are the roof overhang ratio and roof pitch angle. Computational Fluid Dynamics (CFD) analysis embedded in ANSYS FLUENT 14 was used to perform the numerical simulations in order to study the influence of overhang ratios and roof pitches with respect to the pressure distribution and wind flow pattern. Prior to that, a validation work was carried out based on the results obtained from previous work as means to ensure the correct usage of the input data and commands embedded in ANSYS FLUENT 14. The validation exercise showed good agreement with the reference model. The actual study modelled an isolated single storey model with varying overhang ratio and roof pitches. The results showed that the magnitude of the net pressure coefficients was inversely proportional to the magnitude of the overhang ratio in most of models. The 12° roof pitch with 0.31 overhang ratio produced the most highest negative pressure coefficient (suction) at the overhang roof. On the other hand, the formation of recirculation zone and mixing layers were found to be relatively similar for 27° and 22° roof pitches. Similar trend was also observed for 17° and 12° roof pitches. It can be concluded that larger net pressure (suction) was generated for relatively lower roof pitch. Also, the pattern of streamline flow was affected by the degree of the roof pitch but not to the magnitude of the overhang ratio.
Contributor(s):
Poon Jing Lin - Author
Primary Item Type:
Final Year Project
Identifiers:
Accession Number : 875006556
Language:
English
Subject Keywords:
roof damages disaster; non-engineered houses; roof pitch angle
First presented to the public:
6/1/2016
Original Publication Date:
5/25/2018
Previously Published By:
Universiti Sains Malaysia
Place Of Publication:
School of Civil Engineering
Citation:
Extents:
Number of Pages - 65
License Grantor / Date Granted:
  / ( View License )
Date Deposited
2018-05-25 15:23:00.231
Date Last Updated
2020-05-28 19:01:11.16
Submitter:
Mohd Jasnizam Mohd Salleh

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