基于GEKO湍流模型的JBC流场数值模拟

Numerical simulation of JBC flow based on GEKO model

[目的]两方程模型是RANS工程计算中常用的湍流模型,其中SST k-ω湍流模型具有良好的壁面距离自适应性和逆压梯度流预报能力。然而,湍流模型构造过程中引入的经验性参数使得湍流模型不具普适性,为此,研究采用引入流动控制参数的方法提高湍流模型对船舶流场的适用性。[方法]在经典SST k-ω湍流模型的基础上,GEKO(Generalized k-ω)湍流模型通过引入流动分离参数C_(S)和旋转修正参数C_(RC)分别控制流动分离强度和流动旋转效应,以提高湍流模型对各类流动的适应性。针对JBC船型,采用SURF程序对其流场进行数值模拟并与试验结果进行对比,以考察不同设置下新参数对船体阻力、伴流场和压力分布的影响。[结果]计算结果表明,与经典SST k-ω湍流模型相比,GEKO湍流模型中C_(s)和C_(RC)的设置会影响到JBC船型的阻力预报及伴流场预报。[结论]湍流模型的参数化修正具有提高湍流模型适应性和精确度的潜力,对湍流模型工程应用改进具有参考价值。

[Objectives]Two-equation models are the turbulence models most commonly used for RANS calculations in engineering applications.The SST k-ωturbulence model is self-adaptive of wall distance and capable of predicting adverse pressure gradient flows.However,as empirical constants are introduced to de-rive turbulence models,none of them are universal for all flow conditions.Flow control parameters are imple-mented in this study to improve the adaptability of turbulence models to ship flow fields.[Methods]The GEKO(Generalized k-ω)turbulence model is based on the classical SST k-ωturbulence model,while also in-troducing separation parameter C_(S) and rotation parameter C_(RC )in order to control the separation intensity and impact of the flow rotation respectively.The new turbulence model is then applied to predict the flow of a JBC ship.In order to inspect the influence of varying settings of C_(S) and C_(RC),the experimental data is compared with the calculation results in terms of ship resistance,wake patterns and pressure distribution.[Results]The comparison results show that the setting of C_(S) and C_(RC) in the GEKO turbulence model can have an impact on the prediction of ship resistance and local wake flow compared to the classical SST k-ωtur-bulence model.[Conclusions]The reasonable parameter tuning of turbulence models has the potential to improve the accuracy and applicability of numerical prediction.This procedure can provide references for the modification of turbulence models in engineering applications.