摘要
采用数值和实验相结合的方法研究了绕轴对称体三维非定常空化流动现象。实验中,采用高速摄像的技术和动态测力系统对绕半球型和平头型轴对称体的非定常空化流场及其动力特性进行了分析,观察了在不同空化数下,绕半球型和平头型轴对称体的空泡形态;测量了轴对称体受到的阻力,并对阻力信号进行了时频分析,得到了在非定常空化阶段,轴对称体动力特征频率。基于实验现象,发展了一种基于密度修正的分域空化流动的计算方法,并与实验结果进行了对比,结果表明:该方法可以较好的模拟绕轴对称体三维非定常空化流动现象。绕不同头型轴对称体的空化流场结构均存在明显的三维非定常流动特性,并且,空化流场形态与动力特征频率存在高度的相关性,不同头型轴对称体的非定常空化流场结构存在较大的差异,半球型轴对称体空泡流动的脉动主要是空泡尾部的高频小脱落引起的,而平头型轴对称体的空泡流脉动成分主要是大尺度的漩涡空泡团的周期性脱落。
Cavitating flows around axisymmetric bodies are studied based on the experiments and numerical simulations.In experiments,a high-speed video camera is used to visualize the flow structures for different axisymmetric bodies and cavitation numbers,and a dynamics measure system is used to measure the instantaneous dynamic characteristic of the axisymmetric bodies.Meanwhile,a density modify based closure model for unsteady cavitating flows which contains multi-phase and time scale information of the cavitating flows is used.Comparisons are made with available measurements of surface pressure distribution to validate the methods.It is shown that the nature cavitation phenomenon around the axisymmetric bodies can be well simulated.There are different miscellaneous patterns of flow and interface for distinct shape bodies,which are strongly correlated with unsteady dynamics characteristics.The differences exist between frequency characteristics of the unsteady cavitating flows around hemispherical and blunt bodies.For the blunt axisymmetric bodies,the frequency characteristics of the low-frequent pulsation seems due to the large scale cloud shedding and is different from the pulsation caused by the local breakup of the cavity at its tail zone of the hemispherical axisymmetric body
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2010年第6期837-844,共8页
Chinese Journal of Hydrodynamics
基金
国家自然科学基金项目资助(50979004)
关键词
空化
轴对称体
空泡形态
脉动特性
cavitation
axisymmetric body
cavity shapes
dynamics characteristic
