Prediction of Developing Turbulent Flow in a Rectangular-Sectioned Curved Duct

The developing turbulent flow in a rectangular-sectioned curved duct with an aspect-ratio of 6 was explored using linear and non-linear high- and low-Re k-ε turbulence models. The impact of the inlet flow conditions and grid density was also studied. It was found that the boundary layer thickness upstream the bend has fundamental influence on the secondary flow, velocity profile and turbulence level. The flow in the straight inlet duct was nearly 2-dimensional. The predicted data using Chen’s model and the quadratic high-Re model agreed well with the experimental data from Kim and Patel [1]. Also Suga’s cubic low-Re model performed well. The quadratic low-Re model, however, predicted thicker boundary layer which gave magnified secondary flow with high levels of shear and turbulence. It is not certain that the used high-Re models would perform well in a fully three-dimensional flow. Suga’s model, however, might perform well in other more complex flows.