Chapter 6, Problem 6.16P

If laminar flow is induced at the surface of a disk due to rotation about its axis, the local convection coefficient is known to be a constant, $h=C,$ independent of radius. Consider conditions for which a disk of radius $r_o=100\text{mm}$ is rotating in stagnant air at $T_{\infty }=20°\text{C}$ and a value of $C=20{\text{W/m}}^{\text{2}}\cdot \text{K}$ is maintained.

If an embedded electric heater maintains a surface temperature of $T_s=50°\text{C,}$ what is the local heat flux at the top surface of the disk? What is the total electric power requirement? What can you say about the nature of boundary layer development on the disk?