Abstract:
This study examines the momentum and heat transfer aspects of the laminar forced-convection induced by a
pulsatile flow of power-law fluids past a heated circular cylinder by numerically solving the time-dependent
momentum and energy equations over the ranges of dimensionless parameters as the cylinder Reynolds number
based on the mean velocity (0.1 � Re � 40), Prandtl number (0.7 � Pr � 100), power-law index (0.3 � n �
1.4), frequency (0 � ω* � π) and amplitude (0 � A � 0.8). The detailed kinematics of the flow and temperature
fields is visualized in terms of instantaneous streamlines and isotherm contours, especially adjacent to the cylinder.
Further detailed insights are developed by examining the distribution of the pressure coefficient and local
Nusselt number along the surface of the heated cylinder at different instants of time during the course of a
periodic cycle. Finally, the overall gross characteristics are reported in terms of the time average drag coefficient
and Nusselt number. It is possible to achieve varying levels of enhancement in the overall mixing of fluid and
heat transfer under appropriate conditions of the amplitude of velocity, Reynolds number and power-law index.
This is explained via the dynamics of the separated flow regions in terms of their growth and collapse during the
course of a pulsation cycle. The fluid shear-thinning behavior promotes heat transfer in line with that seen in
non-pulsating flows and shear-thickening behavior impedes it with reference to the corresponding value in
Newtonian fluids otherwise under identical conditions.
