Cd for 2-d cylinder

Mike Lamar

hi, everyone

I am trying to ues FLUENT to show the relationship between Re and Coeffiecient of Drag for a 2-D cylinder. I tried the range from 10-1E5. Half of the cylinder is applied since I only need mean performance. However, I could not get the correct relationship. The Cd predicted by FLUENT is quite away from classic fluid dynamics book. here are some details of my approach. the half cylinder is in the center of the bottom of the domain, with the other bottoms are set as symetric condition. The diameter of the cylinder is 2. and upstream is x=-5, set as velocity inflow bc. Outflow bc is set at x=+5. At y=5, also set as velocity inflow,use the same value as the inflow boundary. For all the cases, steady and laminar model are usd. And the values in the /reference values/ are correctly adjusted. But the results are still far away. Can anybody give some help on this. Thanks very much.