论文部分内容阅读
分析了广泛存在于湍流运动中的能量逆转现象,揭示了其产生的原因,提出了湍流的色散性质.在此基础上,修改了Boussinesq假设,建立了包含色散效应的新的雷诺应力封闭式和湍流色散系数,给出与不同模型相结合时,湍流色散系数所具有的不同形式,并阐述了湍流运动中能量的传递方向及条件.采用不可压缩平板边界层流动和平面后台阶流动验证了其可信性和优越性.平板摩擦阻力系数及边界层速度型与实验结果吻合良好,平面后台阶流动的流向再附长度、台阶边压力系数及湍流强度等参数均比标准k-ε模型更接近实验结果.结果表明:色散项的加入可以在不显著增加计算量的同时显著改善预测精度,模型具有一定的工程应用价值.
The phenomenon of energy reversal, which is widely existed in turbulent motion, is analyzed, the reason of its occurrence is revealed, and the dispersion property of turbulent flow is proposed. On this basis, the Boussinesq assumption is modified and a new closed-loop Reynolds stress Turbulent dispersion coefficient, the different forms of turbulent dispersion coefficient are given when combined with different models, and the directions and conditions of energy transfer in turbulent flow are given.Using incompressible slab boundary layer flow and back-plane flow, Credibility and superiority.The flat friction coefficient and boundary layer velocity model are in good agreement with the experimental results.The parameters such as the length of the back flow and the pressure coefficient of the step edge and the turbulence intensity are all closer to the standard k-ε model The experimental results show that the addition of dispersion terms can significantly improve the prediction accuracy without significantly increasing the computational load, and the model has certain engineering application value.