Oscillating Flow of Power‐Law Fluids over a Sphere: Drag and Nusselt Number Behavior.

The forced convection flow and heat transfer aspects of an isothermal sphere in an oscillating stream of power‐law fluids in the range of 5 ≤ Re ≤ 120 and 0.3 ≤ n ≤ 1.5 are numerically investigated. The effects of shear‐dependent viscosity and oscillatory flow features on the temporal variation of streamlines, patterns of streaming flows, drag coefficient, and Nusselt number are examined in depth. The power‐law index modulates the transition of the steady streaming flows between two distinct streaming regimes. Overall, shear‐thinning fluids at low oscillation frequencies are observed to yield significant increase in heat transfer. Due to the phase lag in the momentum boundary layer, the drag coefficient exhibits a phase lag ranging from π/2 to 4π/5 whereas the Nusselt number lags by about 50 % of these values. [ABSTRACT FROM AUTHOR]