Hi All. This is my first post, so please forgive me if I am not following protocol somewhere. The question: A mass flows through a lets say a pipe with a rectangular cross section at a constant velocity. I am just trying to figure out all the forces acting on this mass. Of course the gravitation force is easy enough. Then, when I get to the horizontal force (force parallel to the flow) I get confused. 1/2mv^2 gives me KE, but at a constant velocity, I suppose we can assume that the force is zero (if we neglect the drag from the fluid). However, if we do account for the drag in the fluid, I think all I need to do is figure out how much frictional force there is between the fluid and the mass that flows through it. What is the best way to calculate this? I am assuming that the shape of the mass is just a cube. Do I have to do some CFD or something or is there an easy way or reference I can use to figure this one out? I just need to ballpark this figure. Any help would be appreciated. Thanks!