Large eddy simulation of turbulent flow and heat transfer in a rotating rectangular duct

In this paper, large eddy simulations are performed for a fully developed turbulent flow and heat transfer in a rotating rectangular duct. Second-order central difference scheme is employed to discretize the all spatial derivatives, and the convection and viscous terms are treated by Adams-Bashforth and Crank-Nicholson schemes, respectively, in conjunction with the approximate-factorization technique in the wall-normal direction, and the Adams-Bashforth scheme is used in the steamwise for all of them. The dynamic Smagorinsky eddy viscosity model has been used to evaluate the unresolved stresses. The simulations are performed for a Reynolds number of 400 based on the mean frication velocity and the hydraulic diameter, while the Prandtl number (Pr) is assumed 0.71. The rotation number changes from 0 to 5. The code based on mixed numerical scheme is validated through comparing the result of a special case of stationary square duct. The results are in good qualitative agreement with the experiment and computational data available show that the mixed scheme is reliable for current study. The objective of this study is to investigate the behavior of turbulent flow near the wall of the duct with different geometry. The resolved-averaged velocities and temperature distribution are investigated. And the turbulent statistics, including the turbulence intensities and Reynolds stresses, are also investigated. The results show that the effects of system rotation with different orthogonal rotating axes have an important influence on the turbulent flow and heat transfer. It has been found that the turbulent flow structure is changed obviously near the stable wall and unstable wall at high rotation number.