摘要
为了研究轴对称体非定常空化的脉动特性,采用高速全流场显示技术和动态测力系统实验研究了绕半球型和平头轴对称体的非定常空化流场及其动力特性。实验在闭式水洞中进行,采用高速摄影的方法观察了在不同空化数下绕半球型和平头轴对称体的空穴形态,总结了在不同空化数下空泡形态的脉动特性;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,得到了轴对称体阻力在非定常空化阶段的时频特征。结果表明:空泡形态及其对应的动力特征随着空化数的变化存在明显的非定常特性,空化流场形态与动力特征频率存在高度的相关性。并且不同头型轴对称体的脉动特性存在明显的差异,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,空化流场的低频特征频率与空泡的大断裂相对应。
In order to study the fluctuating hydrodynamics around axisymmetric bodies,the unsteady characteristics of cavitating flows around hemispherical and blunt bodies are investigated experimentally.Experiments are carried out in a rectangular test section of a cavitation tunnel.A high-speed video camera and dynamic force measurement system are used to record the unsteady cavitating flow patterns and the resistance of axisymmetric bodies under different cavitation conditions.Also,the fluctuating hydrodynamic characteristics are obtained.The results show that cavity shapes reveal the miscellaneous patterns of flow and interface in different development stages,which are strongly correlated with unsteady dynamics characteristics.Frequency characteristics of the unsteady cavitating flows are different around different hemispherical blunt bodies.For the blunt axisymmetric bodies,the frequency characteristics of the low-frequent pulsation are mainly due to the large-sale 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
《工程力学》
EI
CSCD
北大核心
2012年第2期239-244,共6页
Engineering Mechanics
基金
国家自然科学基金项目(50979004)
关键词
空化
轴对称体
时域与频域分析
脉动特性
高速全流场显示技术
cavitation
revolution body
time and frequency domain analysis
pulsation
high speed flow visualization
