Effect of temperature dependent viscosity on entropy generation in transient viscoelastic polymeric fluid flow from an isothermal vertical plate

• Published in: Physica A 2018-11, Vol.510, p.426-445
• Main Authors: Janardhana Reddy, G., Kumar, Mahesh, Anwar Beg, O.
• Format: Article
• Language: English
• Subjects: Bejan number; Entropy generation; Free convection; Implicit method; Second-grade fluid; Thermal polymer processing; Vertical flat plate
• ISSN: 0378-4371; 1873-2119
• DOI: 10.1016/j.physa.2018.06.065

A numerical investigation of the viscosity variation effect upon entropy generation in time-dependent viscoelastic polymeric fluid flow and natural convection from a semi-infinite vertical plate is described. The Reiner–Rivlin second order differential model is utilized which can predict normal stress differences in dilute polymers. The conservation equations for heat, momentum and mass are normalized with appropriate transformations and the resulting unsteady nonlinear coupled partial differential equations are elucidated with the well-organized unconditionally stable implicit Crank–Nicolson finite difference method subject to suitable initial and boundary conditions. Average values of wall shear stress and Nusselt number, second-grade fluid flow variables conferred for distinct values of physical parameters. Numerical solutions are presented to examine the entropy generation and Bejan number along with their contours. The outcomes show that entropy generation parameter and Bejan number both increase with increasing values of group parameter and Grashof number. The present study finds applications in geothermal engineering, petroleum recovery, oil extraction and thermal insulation, etc. •Entropy generation on unsteady flow of viscoelastic polymeric fluid is investigated.•Temperature dependent viscosity effect is studied.•Average momentum and heat transport coefficients have involved the investigation.•Entropy and Bejan lines are discussed for different values of physical parameters.•Flow-field profiles for second grade fluid differs with Newtonian fluids.