Coefficient of drag of cylinders
 

Hi, i have a probleme with the drag's coefficient. I am with a 2-D axissymetric problem for a flow over a modified cylinder (a rocket). L=10m , D=0.5m and Mach=1.3

It seems that the probleme is the "reference value". I don't know the right value for the "Area" and the "Lenght".

Can you help me ?

Thank's