convective heat transfer coefficient

Fluu

Hello everybody! I want to calculate the convective heat transfer coefficient of a cylinder with Fluent. - diameter of the cylinder : d = 0,1524 m - temperature of the cylinder: Tcyl = 273,15 K - temperature of the airflow: Ta = 268,30 K - air velocity : u = 90 m/s - air pressure : p = 100 000 Pa - y+ : between 20 and 50

at "XY Plot" - "Wall Fluxes" - "surface heat coefficient" I receive a value hc=90 W/m²K at the stagnation point.

In an article about NASAs LEWICE, they maintain a value of hc=170 W/m²K.

In another article, there is a equation für the coefficient for a cylinder: hc = thermal conductivity * Nusselt number/diameter with Nusselt Number = 1,14 * (Prandtl^0,4)*(Reynold^0,5); there you get a value hc = 165 W/m²K

Do I have to consider something tricky with fluent because my value is pretty low?