Study on shaking phenomenon of branches by strong wind and windbreak structure.

强风作用下树枝晃动现象及防风结构研究

• 批准号: 07660351
• 负责人: TANAKA Hiromichi
• 金额: $ 1.15万
• 依托单位: Tokai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07660351/
• 关键词: Typhoon disaster; Fruit drop; Shaking blanche; Windbreak structure; ヤング率

Many apples dropped by a Typhoon 9119 in Aomori Prefecture, and fruiters sustained great damege.In this studies, first, we studied on the turbulent characteristic of wind near the ground, we elucidated a shaking phenomenon of branches by the strong wind, and considered the windbreak structure.As the result of them we obtained the following the concluding remarks.(1) Horizontal wind velocity is the structure to combine the low frequency and the hight frequency.(2) The turbulent intensity of horizontal and vertical wind velocity increases as horizontal wind velocity increases.(3) The Young's modulus of the branches of apple was E=2.4-4.0gf/cm^2 in the like-values for another fruit trees (pear, persimmon and peach).(4) The fluctuations of apples by wind are large in the direction of back and forth are larger than the direction of rise and fall, right and left.(5) The fluctuations of apples by wind influenced on the magnitude of fluctuating velocity more than the magnitude of velocity.(6) The shaking branches and apples were related to the gustiness.(7) The fluctuations of apples behind the windbreak net were not influenced by the strength and the fluctuations of the wind speed.

9119号台风在青森县造成了许多苹果掉落，果树遭受了巨大的损失。本研究首先研究了近地面风的湍流特性，阐明了强风引起树枝晃动的现象，并考虑了防风结构。根据这些结果，我们得到了以下结论。(1)水平风速是将低频和高频结合的联合收割机结构。(2)随着水平风速的增大，水平风速和垂直风速的紊动强度均增大。(3)苹果枝条的杨氏模量E = 2.4-4.0gf/cm~2，与梨、柿、桃等果树的杨氏模量E = 2.4-4.0gf/cm~2相近。(4)苹果受风的波动在前后方向上较大，在升降、左右方向上较大。(5)风对苹果的扰动对脉动速度大小的影响大于对速度大小的影响。(6)摇晃的树枝和苹果与阵风有关。(7)防风网后苹果的波动不受风力大小和风速波动的影响。

项目成果

金子仲一郎・田中博通: "9119号台風のリンゴ被害調査と地形モデルによる被害地域の流れの可視化" 八戸工業高等専門学校紀要. 31. 41-46 (1996)

Nakaichiro Kaneko 和 Hiromichi Tanaka：“第 9119 号台风对苹果造成的损害的调查以及使用地形模型对受影响地区的水流进行可视化”《八户工业大学通报》31. 41-46 (1996)。

M.Minami : H.Tanaka :"Flow Visualization of Windbreak Net and Submerged Breakwater Using PTV" Journal of the Visualization Society of Japan. Vol.16, Suppl., No.1. 231-234 (1996)

M.Minami：H.Tanaka：“使用 PTV 的防风网和水下防波堤的流动可视化”日本可视化学会杂志。

田中博通・南將人: "ネット背後の流れの可視化と計測" 日本流体力学会誌「ながれ」. 15・別冊. 315-316 (1996)

Hiromichi Tanaka 和 Masato Minami：“网后流动的可视化和测量”日本流体动力学学会杂志“Nagare”15/特刊315-316（1996）。

H. Tanaka: "Flow Visualization Behind Windbreak Net" 4th Asian Symposium on Visualization. 4. (1996)

H. Tanaka：“防风网背后的流可视化”第四届亚洲可视化研讨会。

H.Tanaka,M.Minami: "Flow Visualization Behind Windbreak Net" Proceedings of the fourth Asian symposium on visualization. 353-356 (1996)

H.Tanaka，M.Minami：“防风网背后的流可视化”第四届亚洲可视化研讨会论文集。