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UNSTEADY VERTICAL WIND FORCES APPLIED ON A LARGE ROOF

Research Project

Project/Area Number 08455264
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Building structures/materials
Research InstitutionOsaka City University

Principal Investigator

TANIIKE Yoshihito  Osaka City University, Fac.of Engineering, Prof., 工学部, 教授 (00111980)

Co-Investigator(Kenkyū-buntansha) NISHIMURA Hiroaki  General Building Research Corporation, 室長
OKANAN Hiroo  Osaka Prefectural College of Technology, Dept.of Civil Engineering, prof., 建設工学科, 教授 (20111924)
TANIGUCHI Tetsuro  Osaka City University, Fac.of Engineering, Research Assoc., 工学部, 助手 (30231418)
KIUCHI Tatsuhiko  Osaka City University, Fac.of Engineering, Lecturer, 工学部, 講師 (30112527)
Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1997: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1996: ¥2,700,000 (Direct Cost: ¥2,700,000)
KeywordsPOD Analysis / Stagnation Point / Conical Vortex / Switching / Flow Visualization. / 風圧測定実験
Research Abstract

Generally the horizontal wind force is mainly considered for the design of structures. However, in the case that the structure is located at a hilly country or has a large-span roof, the instantaneous vertical wind force must be considered. This vertical wind force is considered to be induced by vortices generated on a roof. The present study is aimed to make clear the mechanism of these vortices by means of the flow visualizations and the wind tunnel experiments concerned with the pressure applied on the roof and the wall of the model.
The flow visualizations with the cubic and the square roof models were carried out when the incident flow is for oblique angle, using the mist vaporized of the alcohol solution. The flow patterns on the roof was observed with laser sheets and a strobe light. On the roof of the square roof model, a pair of conical vortices is observed which are steady similar to those generated on the delta wing. On the other hand, on the roof of the cubic model only one … More conical vortex exists and this changed the side almost alternately. In the following this phenomenon is called the switching.
In order to investigate the cause why switching is induced, the wind tunnel experiments were carried out, which pressures applied on 96 points on the roof and the wall of the model were measured. The obtained time series of pressures were analyzed by Proper Orthogonal Decomposition (POD). POD is the available technique to find the systematic structure from many time records of the pressure which fluctuates randomly. As a result of the case of the model with flat horizontal roof, the most distinguished mode was as follows. The pressures on one side of the roof fluctuate in the opposite direction to of the other side. On the other hand, the pressures on one side wall fluctuate in the opposite direction to the pressures of same side of the roof and the other side wall. These results of the flow visualization and POD analysis means that the conical vortex generated on the opposite side to the wall which the stagnation point exists on. Consequently it is clarified that the switching of conical vortex on the roof is closely related with the position of the stagnation point on the wall. Less

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] Taniike, Y.: "Wind load and wind-induced response estimations in the Recommendations for Loads on Buildings,AIJ 1993" Engineering Structures. Vol.18 No.6. 399-411 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 谷口 徹郎: "陸屋根面上の円錐渦に関する可視化風洞実験" 日本建築学会構造系論文集. 第488号. 31-37 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 谷口 徹郎: "負担面積と時間遅れを考慮したドーム屋根面圧に関するPOD解析" 第14回風工学シンポジウム. 323-328 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] (社)日本鋼構造協会: "構造物の耐風工学" 東京電機大学出版局, 688 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Taniike, Y.: "Wind load and wind-induced response estimations in the Recommendations for Loads on Buildings, AIJ 1993" Engineering Structures. 18-6. 399-411 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Taniguchi, T.: "Flow Visualization on Conical Vortex on a Flat Roof" Journal of Structural and Construction Engineering (Transactions of AIJ) (in Japanese). 488. 31-37 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Taniguchi, T.: "POD Analysis with Weighted-Area and Time-Lag Pressures on a Spherical Roof" Proceedings of the 14th National Symposium on Wind Engineering, (in japanese). 323-328 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Japanese Society of Steel Construction: Wind Engineering on Buildings and Structures. Tokyo Denki University, 688 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 村松大輔: "陸屋根面上に形成される円錐渦のスイッチングについて(その1 屋根面の勾配が円錐渦に与える影響)" 日本建築学会大会学術講演梗概集. B-1. 217-218 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 榊陽一: "陸屋根面上に形成される円錐渦のスイッチングについて(その2 壁面の有無が陸屋根面上の円錐渦に与える影響)" 日本建築学会大会学術講演梗概集. B-1. 219-220 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 谷池義人: "陸屋根面上に形成される円錐渦のスイッチングについて(その3 円錐渦の強さと圧力の関係)" 日本建築学会大会学術講演梗概集. B-1. 221-222 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] (社)日本鋼構造協会: "構造物の耐風工学" 東京電機大学出版局, 688 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] Taniike, Y.: "Wind load and wind-induced response estimations in the Recommendations for Loads on Buildings, AIJ 1993" Engineering Structures. Vol. 18 No. 6. 399-411 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 谷口徹郎: "陸屋根面上の円錐渦に関する可視化風洞実験" 日本建築学会構造系論文集. 第488号. 31-37 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 谷口徹郎: "負担面積と時間遅れを考慮したドーム屋根面圧に関するPOD解析" 第14回風工学シンポジウム. 323-328 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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