带攻角轴对称体自然空泡流脉动特征的数值分析

发布时间：2018-04-27 12:23

本文选题：空泡流 + RANS方程　；参考：《力学季刊》2017年02期

【摘要】：采用雷诺平均NS方程对轴对称体自然空泡流的脉动过程进行了数值模拟.采用通过降低两相过渡区域内湍流涡粘性系数的方法,实现了基于RANS方程的三维轴对称体自然空泡整体脱落过程的数值模拟.与1/4平头轴对称体自然空泡流实验结果比较,空泡大断裂的脱落频率计算值与实验数据基本一致.数值模拟结果表明,在空化数相同条件下,头型变化对空泡成长及脱落有着明显的影响,半球头模型的空泡长度较短,脱落频率较大,而平头模型的空泡长度更长,脱落频率较低.零攻角条件下,自然空泡在大断裂和脱落过程中也呈现非对称性的空泡形态.在小攻角条件下,攻角增大会使得背流侧空泡长度变大,脱落频率略有减小.当攻角大于8度时,空泡的整体脱落规律性受到抑制.
[Abstract]:The Reynolds average NS equation is used to simulate the pulsation process of axisymmetric natural cavitation flow. By reducing the viscosity coefficient of turbulent vortices in a two-phase transition region, the numerical simulation of the whole falling off process of three-dimensional axisymmetric body natural cavitation based on RANS equation is realized. Compared with the experimental results of 1 / 4 flat head axisymmetric natural cavitation flow, the calculated values of the falling off frequency of the large cavitation fracture are in good agreement with the experimental data. The numerical simulation results show that, under the same cavitation number, the change of the head shape has a significant effect on the cavitation growth and shedding. The hemispherical model has shorter cavitation length and larger shedding frequency, while the flat head model has longer cavitation length. The frequency of shedding is low. Under the condition of zero angle of attack, natural cavitation also presents asymmetric cavitation in the process of large fracture and shedding. Under the condition of small angle of attack, the increase of attack angle will cause the length of cavitation to increase, and the frequency of shedding will decrease slightly. When the attack angle is greater than 8 degrees, the regularity of the whole falling of the cavitation is restrained.
【作者单位】：上海交通大学工程力学系水动力学教育部重点实验室;
【基金】：国家自然科学基金(10972138,11632012)
【分类号】：O35

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