Laminar momentum and heat transfer phenomena of power-law dilatant fluids around an asymmetrically confined cylinder

The present study focuses on the flow across an asymmetrically confined (heated) cylinder in a channel for fluids obeying Ostwald-de Wale (power-law) equation for the settings: Reynolds number (Re) = 1-40, power-law index (n) = 1-1.8, gap ratio (gamma) = 0.375-1, blockage ratio (beta) = 0.2-0.5 and Prandtl number (Pr) = 1-50. Total drag coefficient and its individual components have been analyzed as a function of Re, beta, gamma and n. The overall drag coefficient was found to increase with blockage and behavior of fluid, while it drops gradually for increasing Re. The asymmetrical configuration is seen to mitigate the overall as well as individual drag coefficients. The surface heat transfer coefficient in the form of average Nusselt number and the Colburn heat transfer j(h) factor has been thoroughly discussed. Heat transfer rate is found to increase with increasing Reynolds number and wall confinement, while increasing dilatant behavior impedes the same. As expected, heat transfer results have been reconciled in a single curve by way of the Colburn j(h) factor. The j(h) factor is found higher for the symmetric case as compared to the asymmetric case. (C) 2014 Elsevier Masson SAS. All rights reserved.