无壁面参数低雷诺数非线性涡黏性模式研究

STUDY OF WALL-PARAMETER FREE LOW- REYNOLDSNUMBER NONLINEAR EDDY-VISCOSITY MODEL

建立了一个低雷诺数的非线性涡黏性湍流模式，该模式的一个显著特征是它不包含壁面 参数（如ｙ＋，ｎ等），因而特别适用于复杂几何流场的计算，本模式在几种包括回流、分离、激 波等典型流动中进行了验证，结果令人满意。

In complex wall-bounded turbulent flows, the 'universal' behavior of the law of wall is often not observed and the application of the wall-law in conjunction with linear two-equation turbulence models fail to give accurate predictions. For these flow calculations low- Reynoldsnumber high-order models are required, for instance, full Reynolds-stress transport model and explicit algebraic stress model. In most of these models, wall-distance or normal unit vector to the wall appears in damping functions or wall-reflection term. These wall parameters are difficult to define when the flow geometry is complex. A wall-parameter-free low-Reynolds-number high-order turbulence model is thus of great benefit to the prediction of complex wall-bounded turbulent flows. Based on the turbulence near-wall asymptotic behavior, this article presents a low- Reynoldsnumber nonlinear eddy-viscosity model. A particular feature of the model is that it contains no wail parameters like y+, n which are difficult to define in complex flow geometry. The turbulence time scale in the model is modified to adapt to Kolmogorov time scale very close to the wall while remaining the eddy-turnover time scale away from the wall. To validate the performance of these models, a number of test cases have been calculated and results are compared with DNS or experiment data which include fully-developed channel flow, sink channel flow, flow through an asymmetric plane diffuser, ONERA A-Airfoil flow, shock/boundary-layer interaction. The results are very satisfactory as compared with experiments or DNS data which shows the present model can be applied to the calculations of a wide range of complex flows with practical significance and exhibits superior performance than linear two-equation turbulence models.