Calculation of Coefficient of Drag of simplified car model.
 

Hi Friends,
I am trying to analyse the simplified car model of length 410mm in Ansys Fluent 15 and I am fixing the fluid velocity as 14.95 m/s and computational domain dimensions as L=2000mm, W=1200mm, H=1000mm and I calculated reynolds no as 4.207e5 and turbulent intensity as 0.0311 and hydraulic diameter as 1.090.
I had entered the boundary condition for Velocity inlet with above calculated values Turb.intensity, Hy dia, then pressure oulet with K and Epsilon as default values as 1 for both. The result shows [B]Cd value shows 0.16 but the actual Cd value of the model is 0.3, So kindly anyone assist me that where I had done the mistake.
Formulas I had used are
Re=(rho*14.95*0.41)/1.69e-5)
I=0.16(re)^(-1/8)
Hy dia=(4*1*1.2)/Perimeter of domain
Kindly anyone reply me as soon as possible.

Thanks in advance.