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基于可变时间间隔平均方法,提出了一种不可压缩湍流多尺度模型及平均流动方程.与传统的单尺度湍流模型不同,该模型在建立的过程中,保留了湍流的多尺度特性,结合平均流动方程,可以更好地预测湍流流场特征.通过模拟平面后台阶流动和不对称平板扩压器流动,并将预测结果与标准k-ε模型的预测结果对比,初步验证了其可信性及优越性.结果表明:计算所得的平面后台阶流动的流向再附长度与台阶边压力系数比比标准k-ε模型提高精度约20%;平板扩压器流动的回流区位置误差约为7%、倾斜壁面摩擦因数误差约为5%,而标准k-ε模型未能预测出分离现象.可以看出该模型适用于典型的分离流动,在湍流流场的预测中表现优异,具有一定的工程应用价值
Based on the method of variable time interval averaging, an incompressible turbulence multi-scale model and mean flow equation is proposed. Different from the traditional single-scale turbulence model, this model preserves the multi-scale turbulence characteristics in the process of establishment, Flow equation can better predict the turbulent flow field characteristics.Through the simulation of plane flow backflow and asymmetric plate diffuser flow, and the prediction results with the standard k-ε model of the predictive results preliminary verify its credibility And the superiority.The results show that the accuracy of the flow length re-attachment length and the step edge pressure coefficient is about 20% higher than that of the standard k-ε model, and the error of the backflow area of the flat diffuser is about 7% , The error of the friction coefficient of the inclined wall is about 5%, while the standard k-ε model can not predict the separation phenomenon.It can be seen that the model is suitable for the typical separation flow and has excellent performance in turbulent flow field prediction and has certain engineering Value