摘要
为了研究热力学效应对空化流动结构的影响,采用实验的方法研究了水温为6℃、25℃和45℃时绕水翼的非定常空化流场。利用高速全流场显示技术,观察了不同水温下绕水翼的空化流动形态,并利用数字粒子图像测速仪(DPIV)测量了其速度和涡量分布。结果表明:随着水温的升高,空穴区域减小,空穴长度减短。在相同的空化阶段,热力学效应对空泡的脱落周期影响较小,脱落周期基本不变。热力学效应对速度和涡量影响较大的区域主要集中在空化区域及其与主流区的交界面处。随着水温的升高,低速高脉动区域逐渐减小,且对应的速度值略有升高,导致速度梯度减小,湍流脉动强度降低。同时发现,涡量区域对应于流场中具有速度梯度的区域,上下涡量区域随着水温的升高减小,涡量值降低。
In order to investigate the influence of the thermal effect on the unsteady cavitation structure, the unsteady characteristics of cavitating flows under 6 ℃, 25 ℃ and 45 ℃ around Clark-y hydrofoil are investigated by experimental methods. A high-speed video camera is used to visualize the flow structures under different cavitation numbers. The digital particle image velocimetry （DPIV） is employed to measure the velocity and vorticity distribution. The results show that the cavity region becomes smaller and the cavity length is shorter with temperature increasing. But at the same cavitation regimes, the influence of the ther- mal effect on the cavity shedding cycle is small and the shedding cycle is basically the same. The region which shows larger influence of the thermal effect on the velocity and vorticity distribution is major in the cavitation region and the interface between the cavitation region and main free-stream region. The high- fluctuating region with lower velocity becomes smaller and the specific velocity value increases slightly with temperature increasing. It results that the velocity gradient decreases and the turbulence fluctuating intensity decreases with temperature increasing. It to the region which has higher velocity gradient, with temperature increasing. can be also found that the vorticity region is corresponding the upper and lower vorticity region and its value decrease
出处
《船舶力学》
EI
CSCD
北大核心
2013年第4期327-335,共9页
Journal of Ship Mechanics
基金
国家自然科学基金资助项目(50979004)
高校博士学科专项科研基金(200800070027)
关键词
热力学效应
DPIV
空化形态
流速分布
涡量分布
thermal effect
DPIV
cavitation shape
velocity distribution
vorticity distribution
