I'm currently doing a CFD project. This project is actually a simulation of a modeled truck in a wind tunnel. I need to calculate the Drag Coefficient of the truck. Everything is done as calculated and estimated but the result seems to be wrong. I had the formula right and the others seems ok. I suspect is the result from the simulation. Anything u all need to help me solve this problem or any tips on how to solve it, please let me know. Thanks a lot.

Dear Eric,

This is rather tricky but I have the following suggestion. If the order of your experimental and computational results are nearly same or not much different, the roughness in the model could be playing a role. And then it becomes necessary to know the conditions you are simulating and the true conditions that actually existed. Any discrepancy in data could result in erroneous results. I believe that the drag is the single-most important factor in such a simulation and has to be correctly estimated. Thats all with the information I can gather from your question.

Hope it helps

Ganesh