風洞実験によるかわらの振動と飛散現象の研究: 第3報，強風雨発生装置によるかわら屋根の漏水評価

摘要

かわらに関する暴風時の災害は飛散災害に留まらrnず，漏水災害も重要な課題となっている．漏水を取rnり扱う試験は大別して，圧力箱方式と送風散水方式rnが挙げられる．圧力箱方式は，加圧または減圧するrnための装置を用いて模擬的な風圧を再現することがrn出来る．一方，送風散水方式は，送風機及び散水装rn置で構成され，実際の風雨の流れに近い状態で試験rnを行うことが出来る．しかし，両者一長一短の特徴rnを持ち，ともに暴風雨災害の実状を忠実に再現してrnいないのが現状である．%In previous investigations, a series of wind tunnel tests was conducted on the vibration and scattering behavior of full-sized model of roof tiles, which were used widely for roofings of Japanese wooden dwellings. As a result, the mechanism of vibration and scattering of roof tiles could be understood. This paper describes a water leak test of roof tiles. The 100 roof tiles were set up on 10 lines and 10 rows on the pitched roof in the downstream of the flow from the wind tunnel. The flow velocity was increased gradually from the low velocity to the high velocity, and the effects of the wind on the roof tiles were investigated by the water leak test. The experimental apparatus for the purpose of reproducing the wind and the rain was used. The situation of the water leak test was filmed by video camera. Two accelerometers were simultaneously used. The roof tiles which showed significant vibration at any velocity were found in a series of experiments and the accelerometers were attached to the two neighboring roof tiles on the model roof. The water leak phenomena in the experiment by using the artificial rainfall apparatus are discussed in this paper. Some mechanisms with relatively large amplitudes at low-frequency vibrations, which caused water leak phenomena were made clear.