Title: Numerical Analysis of Three-Dimensional Turbulent Sructure in a Periodicaly-Ribbed Channel.
Abstract:This paper presents a numerical analysis to investigate three-dimensional turbulent structure and fluid flow behavior in a rectangular channel flow with streamwise-periodic ribs mounted on facing wall...This paper presents a numerical analysis to investigate three-dimensional turbulent structure and fluid flow behavior in a rectangular channel flow with streamwise-periodic ribs mounted on facing walls. In the calculation, an algebraic Reynolds stress model together with boundary-fitted coordinate system is applied to a periodically ribbed channel in order to solve the accelerated, separated and recirculating flows. The calculated results are compared with the experimental results available to examine the validity of the present method. As a result of this calculation, it was found that the present method predicted well the distributions of mean flow velocity and reattachment length. Moreover, the calculated results of turbulent energy and shear stress are in good agreement with the experimental data. Although it seems that the convection term of the Reynolds stress equation has an effect on the distributions of Reynolds stresses in this periodically ribbed channel flow, an algebraic Reynolds stress model, in which convection and diffusion terms are transformed from the differential form to algebraic form, predicts the experimental results of Reynolds stresses with little discrepancy. As regards the secondary flow, calculated flow patterns differ with the experimental results. In calculation, large variations of secondary flow direction are predicted along the streamwise direction whereas the experimental results show an unchanged flow pattern in both regions with and without recirculating flow.Read More