基于高速摄像实验的开放腔体圆柱壳入水空泡流动研究

发布时间：2019-02-18 15:55

【摘要】：基于高速摄像方法,针对入水空泡流动特征和机理,进行了开放腔体圆柱壳垂直入水实验研究.通过对实验现象的观测,发现开放腔体圆柱壳入水运动会形成波动流动和云化流动两种流动方式,结合影像数据,分别描述了两种流动状态下的空泡形态特征,并获得了空泡波动参数的变化规律;对比不同入水速度实验,分析了入水速度对入水空泡流动方式和流动参数的影响;依据流体力学基本理论,分析了入水空泡波动和云化现象的形成机理.结果表明:随入水速度增加,入水空泡依次呈现波动和云化两种流动状态,波动频率与入水速度无关,闭合发生时间随入水速度增加而减小,与Froude数呈线性关系;入水导致开放空腔内部气体涨缩,引起开放端压力场和速度场周期性扰动,空泡截面扩展程度出现差异,形成空泡波动现象;空泡闭合后尾部形成回射流,回射流触及空泡壁面引起壁面流动转捩,形成空泡云化现象.
[Abstract]:According to the characteristics and mechanism of cavitation flow in water, an experimental study on vertical water entry of open cavity cylindrical shell is carried out based on high speed camera method. Through the observation of the experimental phenomena, it is found that the open cavity cylindrical shell moves into the water to form two kinds of flow modes: fluctuating flow and cloud flow. Combined with the image data, the characteristics of cavitation morphology in the two flow states are described respectively. The variation law of cavitation fluctuation parameters is obtained. The influence of water entry velocity on the flow mode and flow parameters of cavitation was analyzed, and the formation mechanism of cavitation fluctuation and cloud phenomenon was analyzed according to the basic theory of fluid mechanics. The results show that with the increase of the velocity of water entry, the flow state of the cavitation is in turn fluctuating and clouding, and the frequency of fluctuation is independent of the velocity of entering water, and the time of closure decreases with the increase of the velocity of entering water, which is linearly related to the number of Froude. The inlet of water leads to gas expansion and contraction in the open cavity, which results in periodic disturbance of the pressure field and velocity field at the open end, and the difference of the expansion degree of the cavitation cross section, resulting in the cavitation fluctuation. After the cavitation is closed, the back jet is formed in the tail, and the flow transition of the wall is caused by the back jet touching the wall of the cavitation bubble, resulting in the cavitation cloud phenomenon.
【作者单位】：哈尔滨工业大学航天学院;
【基金】：黑龙江省自然科学基金(批准号:A201409) 哈尔滨市科技创新人才研究专项基金(批准号:2013RFLXJ007) 中央高校基本科研业务费专项资金(批准号:HIT.NSRIF.201159)资助的课题~~
【分类号】：O35

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