Numerical Investigation of Turbulent Flows in Grooved Channel

초록

In this study, turbulent flows in grooved channel were numerically investigated using LES. When the groove is long enough, there exist the flow structures typically observed in backward-facing step flow, such as free-shear layers, recirculating regions, reattachment and redevelopment, and secondary flows. When the groove is short, the recirculating region is confined in the groove; neither reattchment nor redevelopment occurs. In this case, the recirculation in the groove is very weak, and the whole flow field behaves like a conventional channel flow. As a result, the mean pressure difference between inlet and outlet is decreased, and the region of high turbulence intensity appears in the middle of the upper boundary of the groove. Since the weak recirculation occupies the entire groove, one cannot expect effective mass and heat transfers there.