Viscoelastic fluid flow through an annulus with relaxation, retardation effects and external heat source/sink

Abstract

Analysis of unsteady hydro-magnetic viscoelastic fluid flow through an annulus (bounded by two infinite co-axial circular cylinders) has been made in presence of radiation, periodic pressure gradient and external heat source/sink. To study the viscoelastic effects, Oldroyd fluid model has been used. Governing partial differential equations are converted into ordinary differential equation and are solved analytically using modified Bessel functions of first kind Iυ(z) and second kind Kυ(z). Effects of relaxation and retardation parameters with other flow parameters are shown in graphically and in tabular form and their effects are seen maximum in the central portion of the annular region. Keywords: Relaxation and retardation, Viscoelastic fluid, Modified Bessel function, Shear stress, Annulus, Radiation