Transient entropy analysis for the flow of a second-grade fluid over a vertical cylinder

摘要

This study investigates entropy generation for the unsteady flow of a second-grade fluid over a uniformly heated vertical cylinder. The fluid viscosity is assumed to vary with temperature. The mathematical model of this problem is given by highly time-reliant nonlinear coupled equations and resolved by an efficient unconditionally stable implicit scheme. The time histories of average values of momentum and heat-transport coefficients, entropy-generation and Bejan number, and steady-state flow variables are discussed for several values of non-dimensional parameters arising in the flow equations. The results indicate that entropy-generation parameter and Bejan number increase with rising values of group parameter and Grashof number. The results also show that entropy-generation number declines with increasing viscoelastic parameter.