Thanks for answering me and special for your comments, the y axis is the streamwise velocity of the particles, and the x-axis is the radius of the pipe (from -0.0285 to +0.0285)
The experiment graph shows us the particles’ velocity profile; in the paper, they also offer the velocity profile of the air. I understand that my results will be different since I work with 2D, but I want to get at least closer and have a velocity profile that is not as distorted as the one in my graph.
I have modified the dimensions of the pipe with those of a paper (the other values are the same), to compare my results; however, I was unable to obtain a proper profile of the particles. On the left is the air velocity profile and on the right is the particle velocity profile (still distorted)