Flow and Forced Convection Heat Transfer in Crossflow of Non-Newtonian Fluids over a Circular Cylinder

Abstract

The steady and incompressible flow of power-law type non-Newtonian fluids across an unconfined, heated circular cylinder is investigated numerically to determine the dependence of the individual drag components and of the heat transfer characteristics on power-law index (0.5 e n e 1.4), Prandtl number (1 e Pr e 100), and Reynolds number (5 e Re e 40). The momentum and energy equations are expressed in the stream function/vorticity formulation and are solved using a second-order accurate finite difference method to determine the pressure drag and frictional drag as well as the local and surface-averaged Nusselt numbers and to map the temperature field near the cylinder. The accuracy of the numerical procedure is established using previously available numerical and analytical results for momentum and heat transfer in Newtonian and power-law fluids. The results reported herein provide fundamental knowledge of the flow and heat transfer behavior for the flow of non-Newtonian fluids over a circular cylinder; these results further show that the effect of the power-law index on such behavior is strongly conditioned by the kinematic conditions and less so by the type of thermal boundary condition prescribed at the cylinder surface.

Steady flow of power-law fluids across an unconfined elliptical cylinder

“…At high values of the Reynolds number (20 Re 40), the value of C D increases with an increase in the power-law index for 0.2 E 5; however, this effect gets accentuated at E = 2 and 5. These trends are qualitatively consistent with the literature values for a circular cylinder Chhabra et al, 2004;Soares et al, 2005). The total drag coefficient (C D ) over the range of the Reynolds number (0.01 Re 40), power-law index (0.2 n 1.8) and aspect ratio (0.2 E 5) can be best represented by the following relation:…”

“…The three creeping flow studies Tanner, 1993;Whitney and Rodin, 2001) are in excellent agreement with each other for n < 1, as far as the values of the total drag coefficients are concerned; the corresponding values of the limiting Reynolds number denoting the cessation of the creeping flow regime have been delineated recently (Sivakumar et al, 2006). Likewise, the two independent numerical studies in the two-dimensional steady flow regime for finite values of the Reynolds number (Re 40) (Bharti et al, 2005(Bharti et al, , 2007Chhabra et al, 2004;Soares et al, 2005) are also in good agreement with each other. For the sake of completeness, it is also appropriate to mention here that limited results for the steady flow of powerlaw fluids past confined and unconfined square (Dhiman et al, 2006b;Gupta et al, 2003;Paliwal et al, 2003) and rectangular (Nitin and Chhabra, 2005) cylinders are also available.…”

Two-dimensional Flow of Power-law Fluids over a Pair of Cylinders in a Side-by-Side Arrangement in the Laminar Regime

“…On the other hand, the analogous literature on the flow of power-law fluids past a cylinder is not only of recent vintage but is also much less extensive. Some numerical results are now available on hydrodynamics (D'Allessio and Pascal, 1996;Whitney and Rodin, 2001;Chhabra et al, 2004;, forced convection heat transfer (Soares et al, 2005;, and mixed convection heat transfer (Srinivas et al, 2009;Soares et al, 2009;Bouaziz et al, 2010). However, most of these studies are restricted to the steady flow regime (Sivakumar et al, 2006), very few studies deal with the flow of power-law fluids past a cylinder (Patnana et al, 2009), and heat transfer (Patnana et al, 2010;Soares et al, 2010), in the laminar vortex shedding regime.…”

Laminar Forced Convection Heat Transfer Characteristics from a Heated Cylinder in Water Based Nanofluids

“…In addition to the aforementioned grid-dependency study, the present simulation results have also been compared against the available results of other authors [29,30] for the forced convection in Newtonian fluid from heated circular cylinder. The comparisons between the present numerical results (obtained with mesh MIII ) with the benchmark values (summarised in Table III) are extremely good and entirely consistent with our grid-dependency studies.…”