[wateraction]

Hi, everyone! I don't really understand what velocity angle mean in Fluent, and I'm waiting for a beautiful explaination.
Here is a screenshot about "velocity vectors corlored by velocity angle" on a cross-section,

http://dl.dropbox.com/u/28013317/Velocity-angle.png

plus:The case is "air running downwards in a duct".

Does the velcotiy angle mean the angle that the vectors contacting with the cross-section?

We could see vectors in blue color(with the value between -111 to -113) and in red color(with the value between -76.8 to -78.6). If we consider -90 degree stands for the vectors that is vertical to the cross-section, then vectors in blue color and in red color should be inclined separately to the left and to the right. However, the screenshot shows vectors in blue color and in red color are both inclined to the left, which seems weird.

Thanks for your attention!