Separated flows in three-dimensional ducts with wavy surfaces.

Abstract

A numerical calculation scheme developed for arbitrary velocity and coordinate systems has been successfully employed for the calculation of flows over wavy wall surfaces. A comparison of the prediction and experiment reveals that the present numerical method, when coupled to the two-equation turbulence model, provides a reasonable prediction on the mean velocity and pressure fields, althogh some discrepancy is present in the wall shear stress distributions as a result of the standard near-wall treatment on the wavy walls. Calculation results on a square duct with upper and lower wavy wall surfaces show that the secondary flow activity works not only to enhance the heat transfer rate, but also to shorten the running length for the development of the periodic pattern in the temperature field.