Studies on Unsteady Aerodynamic Forces on Vehicles under a Fluctuating Side-wind

脉动侧风作用下车辆非定常气动力研究

• 批准号: 61550123
• 负责人: OKAJIMA Atsushi
• 金额: $ 1.41万
• 依托单位: Kanazawa University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61550123/
• 关键词: Bluff body; Side wind; Wake vortex; Fluctuation of side-force; Fluctuation of drag force; Vehicle; 風洞実験; ブラフボデイ; 風洞; 変動流体力

The response of aerodynamic forces( a side and a drag forces ) on a vehicle model passing through a wake behind a main tower of a big suspension bridge has been investigated in a wind tunnel. A new device that makes a vehicle model run with a high speed has been constructed. We successfully extract a component due to a vortex-street from the unsteady side and drag forces on a vehicle model which has been neasured at the same time with an unsteady pressure on the side surface of a tower model. As additional experiments, a splitter-plate placed behind the tower model prevents the vortex street from shedding in the wake. Which makes the effects of the surviving velocity-gradient clear and a side and a drag forces on a vehicle which suddenly immerges in a uniform flow also has been measured.Then we have prepared five vehicle models: three cylindrical (2-dimensional) models and two box (3-dimensional) models with a rectangular and a aquare sections, respectively. The results of the present … More study may be summarized as follows: (1) When a cylindrical model passes through the wake of the tower with a splitter plate, the aerodynamic forces are influenced by the effects of an apparent angle of attack, the interference between the flows around a tower and a vehicle, and the effects of transient characteristics of flow. In the case of box models, the aerodynamic forces are governed by the effects of the angle of attack. (2) The fluctuation in a side-force exerted on a cylindrical or a box models corresponds to the fluctuation in a wind velocity due to the vortex-street behind a tower, and the unsteady forces with a constant phase-angle referred to the vortex-movement remarkably increase when the cehicle gets out of the wake. (3) The unsteady forces on a box model respond more rapidly to the cahnge in wind velocity than ones on a cylindrical model. (4) The periods of the unsteady forces on the vehicles are found to get out of order influenced by its passing through the vortex-street. Less

在风洞中研究了通过大型悬索桥主塔后面尾流的车辆模型的空气动力（侧面力和阻力）的响应。一种使车辆模型高速行驶的新装置已经建成。我们成功地提取了由于不稳定侧面的涡街和车辆模型上的阻力而产生的分量，该分量已与塔模型侧面的不稳定压力同时测量。作为附加实验，放置在塔模型后面的分流板可防止涡街在尾流中脱落。这使得幸存速度梯度的影响变得清晰，并且还测量了突然陷入均匀流中的车辆上的侧面力和阻力。然后我们准备了五个车辆模型：三个圆柱形（2维）模型和两个分别具有矩形和方形截面的盒子（3维）模型。目前的研究结果可概括如下：（1）当圆柱模型通过带有分流板的塔筒尾流时，气动力受到表观迎角的影响、塔筒周围流场与车辆之间的干扰以及流动瞬态特性的影响。在盒模型的情况下，空气动力受迎角的影响。 (2) 施加在圆柱体或箱体模型上的侧向力的波动对应于塔后涡街引起的风速波动，并且当小车脱离尾流时，与涡流运动相关的恒定相角的非定常力显着增加。 (3) 盒模型上的非定常力对风速变化的响应比圆柱模型上的非定常力更快。 (4)发现车辆通过涡街时所受非定常力的周期出现紊乱。较少的

项目成果

Taro, NAGAHISA; Atsushi OKAJIMA; Ryuji SHIBATA: "Unsteady Aerodynamic Forces on a Vehicle Model Passing in a Wake" Transactions of the Japan Society of Mechanical Engineers. B53-485. 40-48 (1987)

太郎、长久；

長久太郎: 日本機械学会論文集B編. 485. 40-47 (1986)

长久太郎：日本机械工程师学会会议录，卷 B. 485. 40-47 (1986)

岡島厚: 日本機械学会論文集.

Atsushi Okajima：日本机械工程师学会会议录。

長久太郎: 日本機械学会論文集 B編. 485. 40-47 (1986)

长久太郎：日本机械工程师学会会议录，卷 B. 485. 40-47 (1986)

Atsushi OKAJIMA: "Unsteady Aerodynamic Forces on a Vehicle under a Fluctuating Side Wind" Transactions of the Japan Society of Mechanical Engineers.

Atsushi OKAJIMA：“波动侧风下车辆上的不稳定空气动力”日本机械工程师学会会刊。