Flow in and after the industrial bends are quite important from the flow metering point of view. There is a wide-range of studies focusing on simulations of turbulent flows through curved pipes. For flow metering it is important to know and understand that how the flow develops after a disturbance. There is little information in the literature how the flow develops after such a disturbance. In the present study, we focus on the scaled resolved by a Large Eddy Simulation (LES) of an in-plane and out-of-plane bend at a relatively low Reynolds number 20,000.
LES results served as a benchmark for the RANS simulations using different turbulence models and wall treatments. For all simulations, the integration was performed up to wall that is y+ of 1. From computing effort point of view, it is quite impractical to employ LES approach in industrial environment. Therefore, our objective was to find the most suitable RANS-model of STAR-CCM+ for the above mentioned two situations. Furthermore, we have established and showed the best practiced guidelines for carrying out a Large Eddy Simulation.
The turbulence models that are studied are 2 layer realizable k-epsilon (RKEPS-2L), two layer standard k-epsilon (SKEPS-2L), v2-f k-epsilon (V2F), k-omega Shear Stress Transport (SST), low Reynolds number k-epsilon (low-Re KEPS) and the two-layer Reynolds stress model (RSM-2L). The results reveal that the RKEPS-2L is the only model which can be adopted for both the simulations. Another interesting observation in this study is that k-omega SST model fails to predicts the flow development in both the cases. There is no other RANS model which serves our requirements for both the cases.