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UNSTEADY WIND FORCES IN TATSUMAKI

Research Project

Project/Area Number 06452288
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field Building structures/materials
Research InstitutionOsaka City University (1995)
Kyoto University (1994)

Principal Investigator

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

Co-Investigator(Kenkyū-buntansha) 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)
林 泰一  京都大学, 防災研究所, 助手 (10111981)
丸山 敬  京都大学, 防災研究所, 助手 (00190570)
Project Period (FY) 1994 – 1995
Project Status Completed (Fiscal Year 1995)
Budget Amount *help
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1995: ¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1994: ¥2,900,000 (Direct Cost: ¥2,900,000)
KeywordsTatsumaki / Unsteady Wind Force / Rankine Vortex / Added Mass / Velocity Potential / Morison's Equation / Wind Tunnel Experiment / 渦 / 構造物 / 被害 / 加速度 / ランキン
Research Abstract

The word 'tatsumaki' is used in Japan to designate meteorological phenomena as tornadoes and waterspounts. In surbeys of tatsumaki damage, great differences are often observed in the magnitude of damage to buildings, housings, towers, pylons, poles and signboards, depending on where these structures were located relative to the path of the tatsumaki. Generally, there is little regularity in the direction these structures are torn down or in which way missiles such as roofing tiles, timbers and gravels are scattered. These are results of rotational windstorms and fluctuational velocities, that are characteristic of tatsumakis. As a tatsumaki passes over, the speed and direction of wind will change constantly, creating rapid transitions in the magnitude and direction of wind loads on structures it encounters, both in time and space. Wind forces on bodies induced by unsteady flows are inevitably different from those by steady flows with constant velocity. Therefore, tatsumaki-induced wind … More loads on structures should be different from those induced by typhoons or monsoons, as both can be approximated as steady flows.
In the present study, we assumed the swirling motion of tatsumakis as a Rankine vortex that moves with a constant velocity, and analyzed the unsteady horizontal flow at arbitrary points along the tatsumaki path. By the action of unsteady/accelerating flow, the inertial force is generated on bodies and it can be estimated by the previous experimental data or by the theoretical calculation using the velocity potential of inviscid flow. The inertial force and the drag force which is proportional to the square of fluid velocity were combined and incorporated into the Morison's equation, which was then able to express the total fluid force. The fluctuating fluid forces generated during the passage of a tatsumaki on arbitrary located structures were numerically estimated.
The velocity and acceleration at arbitrary points in the tatsumaki varied continuously with time and both reached maximum at the core of the vortex. The acceleration did not depend on the translation velocity of the tatsumaki and was directed towards the center of the vortex.
It was found that the total wind force acting on structures became maximum at the leeward core of the tatsumaki vortex. The inertial force due to the acceleration of fluid was about 30% of the drag obtained from the square of fluid velocity. The directions in which the bodies are blown down by a tatsumaki may be reversed on the different sides of the path of the vortex center. This was shown to be consistent with the results of a field survey on actual tatsumaki damage. Less

Report

(3 results)
  • 1995 Annual Research Report   Final Research Report Summary
  • 1994 Annual Research Report
  • Research Products

    (28 results)

All Other

All Publications (28 results)

  • [Publications] Taniike,Y.: "Unsteady Horizontal Wind Loadings in Tatsumaki" Journal of Wind Engineering and Industrial Aerodynamics. Vol.51. 117-128 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 西村宏昭: "境界層流中における高層建物no力不安定振動" 日本建築学会構造系論文集. 第456号. 31-37 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 谷池義人: "風方向振動時の非定常空気力〜空力減衰と付加質量の評価〜" 第13回風工学シンポジウム. 323-328 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Taniike,Y.: "Pressure Field and Vortical Structure around Three-Dimensional Prisms" Proc.9th International Conference on Wind Engineering. 183-194 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nishimura,H.: "Unsteady Wind Forces on a Square Prism in a Turbulent Boundary Layer" Proc. 9th International Conference on Wind Engineering. 1995. (195-203)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 谷池義人: "正方形断面をもつ高層建築物の空力不安定性" 京都大学防災研究所年報. 第38号B-1. 65-77 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] 鋼構造と風研究小委員会: "構造物の耐風工学" 日本鋼構造協会, 426 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Taniike, Y.: "Unsteady Horizontal Wind Loadings in Tatsumaki" Jour.Wind Engineering and Industrial Aerodynamics. 51. 117-128 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nishimura, H.: "Aeroelastic Instability of High-Rise Building in a Trubulent Boundary Layr" Journal of Structural and Construction Engineering (Transactions of AIJ). 456 (in Japanese). 31-37 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Taniike, Y.: "Unsteady Aerodynamic Force under Along-Wind Oscilations-Aerodynamic Damping and Added Mass -" Proceedings of the 12th National Symposium on Wind Engineering. (in Japanese). 323-328 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Taniike, Y.: "Pressure Field and Vortical Structure around Three-Dimensional Prisms" Proc.9th International Conference on Wind Engineering. 183-194 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Nishimura, H.: "Unsteady Wind Forces on a Square Prism in a Turbulent Boundary Layr" Proc.9th International Conference on Wind Engineering. 195-203 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Taniike, Y.: "Aeroelastic Instability of Square Prismatic High-Rise Building" Annuals of the Disaster Prevention Research Institute, Kyoto University. 38 B-1. 65-77 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Wind Load Sub-Committee: "Wind Engineering on Buildings and Structures" Japanese Society of Steel Construction. 426. (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1995 Final Research Report Summary
  • [Publications] Taniike,Y.: "Unsteady Horizontal Wind Loadings in Tatsumaki" Journal of Wind Engineering and Industrial Aerodynamics. Vol.51. 117-128 (1994)

    • Related Report
      1995 Annual Research Report
  • [Publications] 西村宏昭: "境界層流中における高層建物の空力不安定振動" 日本建築学会構造系論文集. 第456号. 31-37 (1994)

    • Related Report
      1995 Annual Research Report
  • [Publications] 谷池義人: "風方向振動時の非定常空気力〜空力減衰と付加質量の評価〜" 第13回風工学シンポジウム. 323-328 (1994)

    • Related Report
      1995 Annual Research Report
  • [Publications] Taniike,Y.: "Pressure Field and Vortical Structure around Three-Dimensional Prisms" Proc.9th International Conference on Wind Engineering. 183-194 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Nishimura,H.: "Unsteady Wind Forces on a Square Prism in a Turbulent Boundary Layer" Proc.9th International Conference on Wind Engineering. 195-203 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 谷池義人: "正方形断面をもつ高層建築物の空力不安定性" 京都大学防災研究所年報. 第38号B-1. 65-77 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] 鋼構造と風研究小委員会: "構造物の耐風工学" 日本鋼構造協会, 426 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] Yoshihito Taniike: "Unsteady Horizontal Wind Loadings in Tatsumaki" Jour.Wind Engineeing and Industrial Aerodynamics,. 51. 117-128 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 谷池義人: "風方向振動時の非定常空気力〜空力減衰と付加質量の評価〜" 第13回風工学シンポジウム. 323-328 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 西村宏昭: "境界層流中における高層建物の空力不安定振動〜正方形断面をもつ高層建物の場合〜" 日本建築学会構造系論文集. 456. 31-37 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 西村宏昭: "種々の長方形平面をもつ高層建物の空力不安定振動" 第13回風工学シンポジウム. 341-346 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 谷池義人: "風向方向振動時の空力減衰について" 京都大学防災研究所年報. 37 B-1. 47-55 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 谷池義人: "ジェットによるアクティブ空力制御に関する基礎的研究" 第13回風工学シンポジウム. 443-448 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 谷池義人: "建築技術 7月号 風と渦励振" 306 (1994)

    • Related Report
      1994 Annual Research Report

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Published: 1994-04-01   Modified: 2016-04-21  

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