Momentum and Heat Transfer Characteristics of a Rotating Elliptical Cylinder in Vortex Shedding Flow of Power-law Fluids

A numerical analysis is carried out to comprehend the fluid flow and heat transfer phenomena of non-Newtonian power-law fluid flow around a rotating elliptic cylinder. The investigations are accomplished for the parameters namely aspect ratio of the cylinder, e=0.1; rotational speed of the cylinder, 0.5{less than or equal to}α{less than or equal to}2.0; Reynolds number, Re = 100; power-law index, 0.4{less than or equal to}n{less than or equal to}1.6; and Prandtl number, 1{less than or equal to}Pr{less than or equal to}100. A detailed vorticity and isotherm patterns are presented to demonstrate the vortex shedding and heat transfer phenomenon around the cylinder. The results show the strong dependency of fluid behavior and rotational speed on flow and heat transfer phenomena. At low rotational speed (α{less than or equal to}1.0), the standard vortex-shedding patterns appear. The behavior of the fluid mainly affect the size and strength of the vortices. At higher rotational speed, (α>1.0) a hovering vortex (HV) appears for Newtonian and shear-thinning fluids. The shear-thinning tendency of the fluid encourage the formation of HV, however for shear-thickening fluids HV is not observed. Due to rotational motion of the cylinder the surface Nusselt number vary in periodic manner with time. As expected the Prandtl number and shear-thinning behavior of the fluid encourage the heat transfer from cylinder. The rotational motion of cylinder also favors the heat transfer phenomena. At the end a correlation is presented for time average surface Nusselt number as the function of Prandtl number, fluid behavior, and rotational speed.