中文摘要：

By modifying the Rodi assumption to take account of the influenceof flow curvature, a new curvature modified algebraic stress model(CMASM) is de-veloped from the second moment closure in the generalized curvilinear coordinatesystem. And the explicit form of this ASM, a new curvature modified nonlinear k-εmodel (CMNKE), is derived in the orthogonal curvilinear coordinate system. Thisnew nonlinear k-ε model is further validated by a numerical simulation of a two-dimensional U-type turnaround duct flow. The results show that the CMNKE caneffectively capture the main characteristic of this curvature flow and simulate thedamping effect of the shear stress by a convex curvature and the enhancing effect bya concave curvature. So, this model is a rational and effective simplification to thesecond moment closure.