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浙江大学学报(工学版)
Journal of ZheJiang University (Engineering Science)  2021, Vol. 55 Issue (3): 491-499    DOI: 10.3785/j.issn.1008-973X.2021.03.009
    
Analysis of raindrop trajectory in centrifuge-simulated hypergravity field
Yu ZHAO(),Sheng CHANG,Jian-jing ZHENG*(),Dao-sheng LING,Teng LIANG
College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
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Abstract  

The inertia and the non-inertial frames were established by taking the center of rotation and the tip of the nozzle as the origin respectively in order to analyze the trajectory of raindrops and the rainfall simulation process in the hypergravity field. Then the kinematical and dynamic equations of raindrops were integrated to solve the raindrop motion trajectory. The influences of the value of hypergravity N, the height of the fall, and the initial velocity on the coverage of raindrops falling in a centrifuge-simulated hypergravity field were analyzed. The test conditions were proposed based on rainfall shock effects and rainfall uniformity in the centrifuge. Results showed that the existing methods had large deviations, and the maximum relative error of the offset of the center position of the falling coverage area was 28.22%.

Key words： hypergravity      non-inertial frame      centrifugal simulation      raindrop trajectory      coverage     
Received: 11 February 2020      Published: 25 April 2021
CLC:  TU 411  
Fund:  国家自然科学基金资助项目（51988101）
Corresponding Authors: Jian-jing ZHENG     E-mail: zhao_yu@zju.edu.cn;zhengjianjing@zju.edu.cn
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Yu ZHAO
Sheng CHANG
Jian-jing ZHENG
Dao-sheng LING
Teng LIANG
Cite this article:

Yu ZHAO,Sheng CHANG,Jian-jing ZHENG,Dao-sheng LING,Teng LIANG. Analysis of raindrop trajectory in centrifuge-simulated hypergravity field. Journal of ZheJiang University (Engineering Science), 2021, 55(3): 491-499.

URL:

http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2021.03.009     OR     http://www.zjujournals.com/eng/Y2021/V55/I3/491


离心模拟超重力场下的雨滴运动轨迹分析

为了探究离心模拟超重力场下的雨滴运动轨迹及降雨模拟过程，分别以旋转中心和喷嘴端部为原点建立惯性系和随动坐标系，综合运动学和动力学方程求解雨滴运动轨迹，修正现有研究中雨滴下落轨迹分析的不合理之处. 分析离心模拟超重力场下雨滴下落覆盖范围受超重力N值、下落高度、初始速度的影响程度以及不同方法计算结果相较于推荐方法的误差，以离心机内降雨冲击作用和降雨均匀性要求为判据提出试验建议. 结果表明，已有方法存在较大的偏差，下落覆盖范围中心位置的偏移量最大相对误差达到28.22%.


关键词： 超重力,  非惯性系,  离心模拟,  雨滴轨迹,  覆盖范围 
Fig.1 Diagram of inflight rainfall devices
Fig.2 Coordinate of centrifugal hypergravity
Fig.3 Description of initial velocity of raindrop in local coordinate
Fig.4 Schematic diagram of ideal spraying of a nozzle
Fig.5 Simulated rainfall coverage versus hypergravity multiple
Fig.6 Coverage parameters variation versus hypergravity multiple
N h/m $v{'_0}$/(m·s?1) ea/% eb/% ec/%
10 0.15 10 1.66 0.42 28.60
30 0.15 10 3.02 0.77 23.29
100 0.08 10 1.93 0.49 18.38
100 0.12 10 3.19 0.79 16.10
100 0.15 10 4.16 1.03 15.03
100 0.15 20 2.79 0.71 24.37
100 0.15 30 1.78 0.45 28.22
Tab.1 Relative error of reference [8] method compared with proposed method
Fig.7 Simulated rainfall coverage versus falling distance
Fig.8 Coverage parameters versus falling distance
Fig.9 Simulated rainfall coverage versus initial speed
Fig.10 Coverage parameters versus initial speed of raindrops
Fig.11 Coverage comparison of whether to consider air resistance
Fig.12 Nozzle arrangement design diagram
Fig.13 Nozzle arrangement design diagram
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