Investigation of hysteresis effect of cavitating flow over a pitching Clark-Y hydrofoil  

绕振荡Clark-Y水翼空化迟滞特性研究

作　　者：Mengjie Zhang Fuyong Feng Meijing Wang Zhipu Guo Zhong Kang Biao Huang 张孟杰;冯付勇;王美靖;郭智薄;康忠;黄彪(China North Vehicle Research Institute,Beijing,100072,China;School of Mechanical Engineering,Beijing Institute of Technology,Beijing,100081,China)

机构地区：[1]China North Vehicle Research Institute,Beijing,100072,China [2]School of Mechanical Engineering,Beijing Institute of Technology,Beijing,100081,China

出　　处：《Acta Mechanica Sinica》2022年第6期95-105,I0002,共12页力学学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.52109111,52079004,and U20B2004);the Natural Science Foundation of Beijing(Grant No.3212023);the State Key Program for Basic Research of China(Grant No.MKS20210003).

摘　　要：The objective of this paper is to investigate the hysteresis effect of cavitating flow over a Clark-Y hydrofoil undergoing a transient pitching motion at Reynolds number Re=4.55×105,cavitation numberσ=1.33,pitching frequency f*=2 Hz via combined experimental and numerical studies.A hysteresis phenomenon is observed in the hydrodynamic curve and cavity area in increasing and decreasing of the angle of attackα.The hydrodynamic curves are divided into three regions:Regions A,B and C.For Region A,the lift coefficient of downstroke is lower than that of the upstroke,and the lift coefficient curve of the downstroke is more unstable.The formation and development of counterclockwise trailing edge vortex(TEV)are responsible for the decline and fluctuation of lift during the downstroke,thus leading to the increase of the hysteresis loop.Compared with the upstroke,the hydrodynamic curve in downstroke is shifted laterally to some extent in Region B.The delay effect is the main factor leading to the shift of the hydrodynamic curve,which corresponds to the minimum hysteresis loop.In Region C,the hysteresis loop is maximum and the evolution trend of the hydrodynamic curve is peak-valley opposites.When the direction of oscillation changes,the detachment and dwell time of the cavity are advanced,thus leading to the difference of hydrodynamic curve and the increase of hysteresis loop.本文针对Clark-Y水翼在雷诺数为Re=4.55×10^(5),空化数为σ=1.33,振荡频率为f*=2 Hz时的空化迟滞特性开展试验与数值研究.实验结果发现,绕振荡水翼的水动力特性和空化面积存在显著的迟滞现象.根据升力系数演化特征,将其划分为区域A、区域B和区域C三部分.对于区域A,下行程的升力系数低于上行程,且曲线上下波动较为明显.分析发现逆时针尾缘涡的形成与发展是导致下行程升力系数下降和波动的主要因素,进而促使滞环的形成.在区域B中,下行程的升力系数曲线相对上行程发生一定程度地平移.延迟效应是动力曲线平移的主要原因,进而形成较小的滞环面积.对于区域C,曲线滞环面积是最大的,且上下行程的升力系数演化曲线呈现峰谷相对的趋势.结果发现水翼在下行程阶段,攻角逐渐减小,空化分离和停留时间被提前,进而导致水动力曲线的差异和滞环面积的增大.

关 键 词：Hysteresis effect Cavitating flow Pitching hydrofoil 

分 类 号：O35[理学—流体力学]