Book explanation is confusing me

[Kbonga]

I understand the basic concept of how it happens and what it does, but the book I am reading is confusing me a little

 

[russ_watters]

You're going to have to be more specific about what kind of vortex you're talking about...

...asking a question would be helpful too...

 

[Kbonga]

Basically off of a racecar wing. How does it form, and is it more of an advantage or a disadvantage