How to do correct flow Simulation over a smooth cylinder in SolidWorks ?

I have a cylinder 220mm long and 68.7mm diameter, when I perform a flow simulation of air (temp=20 deg) over it at Re=31000 the value of drag coefficient should be around 1.2. However I am getting around 0.65. Is there any chance to improve the results.
Or is anyone able to conduct the same simulation and share the results.
Thanks