FBM湍流模型水翼空化绕流数值研究

Numerical simulation on cavitating flow around hydrofoil with filter-based turbulence model

为准确模拟云空泡脱落的非定常特性,引入混合密度修正函数,建立了基于独立空间滤波尺度的滤波器湍流模型.联立质量输运型空化模型,采用RNG k-ε湍流模型和滤波器湍流模型数值研究了Clark-y型水翼空化绕流,给出了典型工况下时均速度场、云空化工况下时变空泡形态以及水翼的升、阻力系数等流场和动力特性参数.与实验对比表明,2种湍流模型对水翼稳态空化流场的预测差异较小,RNG k-ε湍流模型不能捕捉到云空泡的非稳态特征,滤波器湍流模型能更好地调节多相流场的湍流粘度,准确捕捉云空泡周期性的脱落细节.

For the purpose of accurately simulating the unsteady characteristics of cloud cavitations shedding, the research focus was first introducing the hybrid density correction function to build a filter-based turbulence model （FBM） based on the independent spatial filter scale. By coupling the mass transport-based cavitation model, the cavitating flows around a Clark-y type hydrofoil, were numerically simulated by using the RNG k-~ turbulence mod- el and the FBM, respectively. Also, the parameters of flow field and dynamic characteristics, such as time-averaged velocity field under the typical conditions, the time-varying cavitation form under cloud cavities conditions and the lift and drag coefficients of hydrofoil, were obtained and compared with the experimental results. The results indicate that the two types of turbulence models are slightly different on the prediction of the steady cavitating flow of the hydrofoil, and the RNG k-ε turbulence model fails to capture the unsteady flow characteristics of cloud cavitating flow. However, the FBM can better accurately simulate the details of the cloud cavitations periodic shedding by regulating the turbulent viscosity of the muhiphase flow field