## 1. Laminar Flow The average Nusselt's number for a flat plate of length $L$ is $Nu_L=0.664Re_L^{1/2}Pr^{1/3}$ valid for $Pr > 0.6$ ## 2. Turbulent Flow $Nu_L=0.0296Re_x^{4/5}Pr^{1/3}$ valid for $0.6 < Pr < 60$