Cylinder simulation-Cp and Separation angle symmetrical plot
 

Hi everyone,

I am a freshman in CFD. Currently I am using Fluent to simulate flow past a circular cylinder at Re = 180, which is a simple case for practising. However, I got two issues, so I post my questions here hopefully I will receive some helps from you.

1. I could not symmetrically plot the pressure coefficient distribution along the cylinder surface. The upper and lower surfaces always have different Cp distribution. So, how can we plot Cp symmetrically? Since I see in many articles they plot it from 0 to 180 degrees and the rest from 180 to 360 is symmetric. I suppose that we choose the data at which Lift coefficient is zero, but even when CL is mostly zero, the graph seems to be asymmetric. (see picture):D

2. How to determine the separation angle? I knew that at the Wall shear stress, or skin friction coefficient equals to zero we can see the separation. But at which positions? at Lift coefficient is zero? and is it symmetrical? (see picture):confused::confused:

Thank you for your attention and I am so appreciated with your help.

Duy Nguyen