基于Level set方法的不同湍流模型在水翼空化流计算中的应用研究

Evaluation of turbulence models for hydrofoil cavitating flows based on Level set method

该文以二维翼型NACA0015为研究对象,基于Level set方法耦合Zwart空化质量传递模型,采用四种湍流模型分别模拟了水翼诱导的非定常空化流过程,计算结果与实验的对比表明:标准k-ε模型无法准确预测尾部空泡的断裂和脱落,通过滤波器模型修正湍流黏性后可以正确预测空泡演变规律;PANS模型参数fk取值0.2时,可以得到满意的空泡演变规律;SAS-SST湍流模型在处理大分离流动上存在明显优势,对尾部空泡周期性脱落规律预测较好。空泡体积变化和监测点压力脉动频率的关系表明空化的发生和演变是空化区域内压力脉动产生的主要原因。

The unsteady cavitating flow around a two-dimensional NACA0015 hydrofoil was simulated based on the Level set method and Zwart cavitation model. Four turbulence models were used to investigate their effects on predicting the evolution of cavitation structures. Compared with the experimental data, it is noted that the standard k-ε turbulence model can not predict the crack and shedding of the cavitation at the tail of the hydrofoil, and the addition of Fliter-Based Model to correct turbulent viscosity can accurately predict the evolvement of cavitation. A suitable value equal to 0.2 in predicting the cavitation structures is parameter fk in the PANS model.The SAS-SST turbulence model has a significant advantage in dealing with large separation flows and predicting the shedding of the cavitation at the tail of the hydro foil. By the analysis of bubble volume evolution and pressure pulsation at monitoring points, it is indicated that the cavitation she dding is the main cause of pressure pulsation in the cavitation region.