Damage process of buildings due to the synergistic effect of the rapidly changing wind speed and atmospheric pressure drop caused by a tornado

2016 Fiscal Year Final Research Report

• Project/Area Number: 26282112
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: Kyushu University
• Principal Investigator: MAEDA Junji 九州大学, 人間・環境学研究科(研究院), 名誉教授 (40128088)
• Co-Investigator(Kenkyū-buntansha): 野田 稔 徳島大学, 大学院理工学研究部, 准教授 (30283972) ; 友清 衣利子 熊本大学, 大学院自然科学研究科(工), 准教授 (30346829) ; 竹内 崇 神戸大学, 工学(系)研究科(研究院), 助教 (80624395)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 竜巻被害 / 気圧急変 / 突風の非定常性 / 風力のオーバーシュート / 竜巻外力

Outline of Final Research Achievements

A new experimental system to make a sudden drop of atmospheric pressure was constructed and the influence of a pressure difference between the inside and outside of a building on the mechanism of tornado damage was clarified. The magnitude of the differential pressure is affected by the descent speed of the outside pressure and the sealing degree of the building, and the sealing degree is governed by the ratio of the building volume and the clearance area. The differential pressure force on the building due to the rapid pressure drop as well as a overshoot wind force caused by gusts can be reproduced by a numerical fluid analysis. The procedure was applied to actual tornado damage to trace the damage mechanism of the building and showed that the estimated value of the tornado wind speed becomes lower than before. Furthermore, by a statistical analysis of strong wind observation records, the probabilistic model of the occurrence of the overshoot wind force was demonstrated.

Free Research Field

耐風工学