I am mainly involved in the validation work. I found that the Cn, Cm values are within 5% to the Wind Tunnel. But the drag is "OFF". The main problem is in Base Drag estimation. I have tried various TURBULENCE MODELS without success. If any one of you have successfully matched the drag coefficient, please contact me. Any suggestions about the selection of TURBULENCE MODEL to simulate wake,would be helpful. I am using 10 degree cone as the standard shape.

you may find that your results are quite typical. i was told by one of my professors that he never saw navier stokes drag predications that were good. typically lift and moment which are aminly due to pressure forces are good but the drag is usually off. many turbulence models were developed for stream line bodies so they probably won't be good for your cone. hopefully others will respond so you and i can see their tips.