troubleshooting tips
 

I am running a drag and lift prediction for flow over an ahmed body and Star-CCM+ consistently gives me under predicted values by around 20%. I have tried changing turbulence models and refining the mesh in the wake but neither helped. My question - what are some basic steps I can take to diagnose the problem?

still need help
 

I have provided these images if they can be of use determining my issues.

Wall Y+

http://s22.postimg.org/eze8y3ptd/yplus.png

Centreline Velocity Magnitude

http://s24.postimg.org/4g38bycn9/velmag.png

Velocity Magnitude from a different piece of software (correct!)

http://s24.postimg.org/yjhr3wfwl/expected_flow.png

Streamlines from Literature

http://s24.postimg.org/ar8fsddvp/expected_2.png