Air is flowing at a velocity of $3\:m/s$ perpendicular to a long pipe as shown in the figure below. The outer diameter of the pipe is $d=6\:cm$ and temperature at the outside surface of the pipe is maintained at $100^{\circ}C$. The temperature of the air far from the tube is $30^{\circ}C$.
Data for air : Kinematic viscosity , $v=18\times10^{-6}m^{2}/s$; Thermal conductivity, $k=0.03\:W/(m.K)$
Using the Nusselt number correlation: $Nu=\frac{hd}{k}=0.024 \times Re^{0.8}$, the rate of heat loss per unit length $(W/m)$ from the pipe to air (up to one decimal place) is __________.
