Chapter 6, Problem 6.27P

An object of irregular shape has a characteristic length of
$L=1\text{m}$ and is maintained at a uniform surface temperature of $T_s=400\text{K}\text{.}$ When placed in atmospheric air at a temperature of $T_{\infty }=300\text{K}$ and moving with a velocity of $V=100\text{m/s,}$ the average heat flux from the surface to the air is $20,000{\text{W/m}}^{\text{2}}.$ If a second object of the same shape, but with a characteristic length of $L=5\text{m,}$ is maintained at a surface temperature of $T_s=400\text{K}$ and is placed in atmospheric air at $T_{\infty }=300\text{K,}$ what will the value of the average convection coefficient be if the air velocity is $V=20\text{m/s?}$