The direction of the tangential force (Fully developed laminar flow in a pipe)

[Minghan]

TL;DR

It's about differential control volume for analysis of fully developed laminar flow in pipe.
Just can't understand why the directions of the tangential forces (shear forces) is like that as the text book show.
I think the directions should be opposite because inner cylindrical surface is carried by central fluid which moves faster and outer cylindrical surface is dragged by the wall.

 

[Chestermiller]

The actual directions will be as you say. That means that the values of the shear stresses indicated in the diagram will be negative.