Nusselt number for a prescribed geometry Nu= -=f(x'.Rec.Pr) Local Nu= _=f(Re.Pr) Average dp" (For a prescribed geometry, is known) dx Many convection problems are solved using Nusselt number correlations incorporating Reynolds and Prandtl numbers The Nusselt number is to the thermal boundary layer what the friction coefficient is to the velocity boundary layer. CI= 2 ou v2 → Re,dy" =0 2Nusselt number for a prescribed geometry (For a prescribed geometry, is known)  Many convection problems are solved using Nusselt number correlations incorporating Reynolds and Prandtl numbers • The Nusselt number is to the thermal boundary layer what the friction coef icient is to the velocity boundary layer.   Re , Pr  Average k hL , Re , Pr Local k hL f * f L L Nu f Nu f x     * * dx dP              * * * 0 * * 2 ,Re , Re 2 2 dx dP f x y u V C L L y s f  