How to creat CFD file like this?

I just downloaded a file from, and I get the csv file including p, U ,velocity, wind factor etc.

Just like this.
I want to know how to creat this file? Can butterfly creat it? I used butterfly to simulate with the example file in the forum,but I can’t find some csv file in my save path.
By the way , what is the meaning of the U value in the butterfly? I know p is pressure but I have no idea about U…
Thank you.