pressure & friction drag co efficients
 

Hello, Can someone please tell me how to find Pressure drag coefficient and friction drag coefficient from the drag coefficient.

I am not aware of any technique for determining the pressure drag coefficient and friction drag coefficient from the total drag coefficient. Perhaps someone else might be more knowledgeable.

The knovledge of the total drag coefiicient is not enough. You should know distribution of pressure (or the velocity gradients) on the surface of the object.

That's a loaded question. Can you explain where you are getting the drag coefficient from in the first place? Experiment, numerical solution, etc...?

Thanks for the reply, I am simulating flow over an elliptical 2d cylinder using ansys(fluent) 14.5. I am getting the Drag coefficient from fluent using solve>monitors options.

That is a much more concise question. Not being familiar with fluent, you may want to direct your question to the fluent forum to see the specifics but there should be an option to calculate pressure and viscous drag separately. If not, then you will need to extract the pressure and shear distributions on your body and integrate to get drag. You can see from the equations that you can separate out the pressure and shear terms and treat them independently. So take cp and calculate cn and ca, then take cf and calculate cn and ca. Then you can transform from normal/axial to lift drag (if you have an angle of attack) and get cd_pressure and cd_viscous.

Thank you for making it very clear :)