Transient Analysis of Forced Convection Along a Wavy Surface in Micropolar Fluids

Abstract

Numerical results for transient laminar-forced convection along a wavy surface in micropolar fluids are presented. A simple coordinate transformation is employed to transform the complex wavy surface to a flat plate, and the obtained nonsimilarity boundary layer equation is solved numerically by the spline alternating-direction implicit method. The effects of micropolar parameter and wavy geometry on the velocity and temperature fields are examined. The transient skin friction and transient local and averaged heat-transfer rates decrease with time. Their axial distributions have a frequency equal to the frequency of the wavy surface, but their crests and troughs do not occur just at the crests and troughs of the wavy surface. The amplitudes of the transient local skin-friction coefficient and the transient local Nusselt number tend to increase as the wavy length and the wavy amplitude-wavelength ratio increases. Furthermore, the transient Nusselt number of a micropolar fluid is smaller than that of a Newtonian fluid everywhere, whereas the transient local skin-friction coefficient of a micropolar fluid is larger than that of a Newtonian fluid just near the leading edge