All correlations for the external flow Nusselt number representing average heat transfer coefficients for spheres have a constant of 2 on their righthand sides: Why? Prove your argument. Problem 11.5....

All correlations for the external flow Nusselt number representing average heat transfer coefficients for spheres have a constant of 2 on their righthand sides: Why? Prove your argument. Problem 11.5. A 0.5-m-wide and 2.5-m-high flat, vertical surface is subject to a UWT boundary condition with T_s
= 70 ◦C. The surface is exposed to air at an ambient temperature of 20 ◦C.

(a) Calculate the distributions of the heat transfer coefficient along the surface.

(b) Assume that air is flowing upward and parallel to the surface with a velocity of 0.05 m/s. Calculate the average heat transfer coefficient for the surface. Does laminar–turbulent transition take place? If so, specify the approximate location of the transition.