Estimates of gust wind speeds in Kyushu area for a wind hazard map

九州地区阵风风速估算，绘制风灾图

• 批准号: 12450227
• 负责人: MAEDA Junji
• 金额: $ 9.15万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12450227/
• 关键词: gust factor; wind disaster; local wind of terrain; NeWMeK; damage rate of houses; map of maximum wind speed; duration of strong wind; 風向別突風率; 局地風; 強風災害; 年最大風速; 強風観測; 広域観測; 風洞実験; 強風被害; 広域風観測

(1) The properties of the gust factors of mean wind speed of over 15 m/s were investigated based on the data of the network of wind measurement in Kyushu (NeWMeK) from 1994 to 2002, which has 122 measurement stations, and the digital information of each terrain. The data of each station are arranged by typhoon or non-typhoon, 16 directions of wind, its weather condition and its topography of terrain.(2) It is indicated that the gust factors in typhoon are higher than those in non-typhoon: 1.9 in typhoon and 1.7 in non-typhoon. When typhoon approaches, the gust factor does not decrease even though the mean wind speeds are high. And so a maximum gust speed is estimated to be a much higher wind speed. Moreover, the maximum gust is much higher in southern wind than in northern wind.(3) The property of increase of wind speed at Shiranui-cho of Kumamoto prefecture was investigated by wind tunnel test. It is found that the temperature gradient of the approaching wind profile affects strongly the increase of wind in the lower layer. The stability of a stratified wind flow is enhanced by a cooled plate using a dry-ice box located at the wind tunnel surface. However, it is difficult to estimate the local wind speed in a mixed area such as a deep river and a deep valley floor.(4) Most of the investigation of the relationship between residential damage rates and wind speeds based on information of damaged residential houses by Typhoon Bart(1999) indicate clearer relation to a instantaneous wind speed. For wind speeds of exceeding 30 m/s, the damage rate exponentially increases. In addition, the duration of wind affects strongly the damage rates in case of wind speeds of over 35 m/s.(5) We have produced the instantaneous maximum wind speed map of Kyushu, by combining our information of gust factors and the map of expected wind speeds for a return period of a hundred years. This wind speed map is applicable to suggest a wind hazard map of residential houses and buildings.

(1) 基于1994—2002年九州测风网(NeWMeK)122个测站的数据，研究了平均风速超过15 m/s的阵风因子特性，并采用数字化各个地形的信息。各站数据按台风与非台风、16个风向、天气状况、地形地势排列。(2)表明台风时阵风因子高于非台风时阵风因子：1.9台风时为1.7，非台风时为1.7。当台风临近时，即使平均风速很高，阵风系数也不会降低。因此，最大阵风速度估计为更高的风速。而且南风时的最大阵风远大于北风时的最大阵风。(3)通过风洞试验研究了熊本县不知火町的风速增大特性。研究发现，逼近风廓线的温度梯度对低层风的增加有强烈影响。使用位于风洞表面的干冰箱的冷却板增强了分层风流的稳定性。然而，在深河、深谷底等混合区域，当地的风速很难估计。(4)住宅受损率与风速关系的调查大多基于受损住宅信息。台风巴特（Typhoon Bart，1999）的研究表明与瞬时风速的关系更清晰。风速超过30m/s时，损坏率呈指数级增加。此外，风速超过35m/s时，风的持续时间对损坏率影响很大。(5)结合阵风因子信息和九州地区的地图，制作了九州瞬时最大风速图。一百年重现期的预期风速。本风速图适用于建议住宅及建筑物的风害图。