U.S.-France Cooperative Research: Turbulence Modelling and Validation

该奖项将支持宾夕法尼亚州立大学航空航天工程系B. Lakshminarayana博士和法国里昂中央学院流体力学与声学实验室Francis Leboeuf教授之间的合作研究。该项目的目标是开发和验证湍流模型。涡轮内的流动现象极为复杂。它是三维的、湍流的、非定常的，旋转、曲率和传热效应对它的影响很大。由于湍流模型不完善，预测这种流动的尝试一直没有成功。Navier- Stokes规范无法捕捉涡轮机和泵中的物理现象，这阻碍了高性能涡轮机械的设计和分析程序的改进。这项合作研究的目的是开发包含旋转、曲率、可压缩性、三维和传热影响的湍流模型。湍流输运方程（基于密度平均）和速度-密度协方差输运方程将被建模，分别导出代数应力输运和代数热通量方程。这些方程与湍流动能和耗散方程以及平均动量方程相结合，应能准确地预测涡轮和泵内的流动和传热场。为了验证模型的准确性，还提出了一个验证实验，包括对湍流应力和能量的各种项的评估，以及湍流热通量输运方程。这项研究将受益于美国和法国研究人员在涡轮机械湍流建模方面的广泛和互补的专业知识。

The award will support collaborative research between Dr. B. Lakshminarayana, Department of Aerospace Engineering, Pennsylvania State University, and Professor Francis Leboeuf, Fluid Mechanics and Acoustics Laboratory, Ecole Centrale de Lyon, France. The objective of this project is to develop and validate models for turbulence. The flow phenomena in turbines is extremely complex. It is three dimensional, turbulent and unsteady, with substantial influence of rotation, curvature and heat transfer effects. Attempts to predict this flow have not been successful due to inadequate turbulence models. The inability of the Navier- Stokes codes to capture the physical phenomena in turbines and pumps has hampered improvements in design and analytical procedures for the development of high performance turbo- machinery. The aim of this cooperative research effort is to develop turbulence models that incorporate the effects of rotation, curvature, compressibility, three dimensionality and heat transfer. The turbulence transport equation (based on density averaging) and velocity-density covariance transport equations will be modelled to derive algebraic stress transport and Algebraic heat flux equations respectively. These equations, coupled with the turbulent kinetic energy and the dissipation equations, and mean momentum equations, should provide accurate prediction of flow and heat transfer field in turbines and pumps. A validation experiment is also proposed to check the accuracy of modelling, including evaluation of various terms contributing to the turbulent stress and energy, and turbulent heat flux transport equations. This research will benefit from the extensive and complementary expertise of the US and French investigators in turbulence modeling of turbomachinery.