Forces appearing on the pipe when a fluid flows in it

[mech-eng]

Hi, I study linear momentum. But I cannot understand enough that how can forces appear on a pipe when fluid flows in the pipe? Fluid have a momentum as m*v how can forces appear on the pipe. I cannot demonstrate the situation in my mind. How can I find a demonstration or a free body diagram for this.

In another words, if a fluid have momentum while entering and going out of a pipe, why are there forces on the pipe?

Thank you.

 

[OldYat47]

Perpendicular to the pipe surface is the pressure in the fluid. Parallel to the pipe surface is fluid drag on the pipe surface. If there are any changes in direction along the pipe those changes in direction cause changes in the fluid's momentum. The pipe reacts to those changes in momentum where the direction changes occur.

 

[mech-eng]

Perpendicular to the pipe surface is the pressure in the fluid. Parallel to the pipe surface is fluid drag on the pipe surface. If there are any changes in direction along the pipe those changes in direction cause changes in the fluid's momentum. The pipe reacts to those changes in momentum where the direction changes occur.

Then can we say that when a fluid flowing in a pipe, probably because of viscous effects, fluid apply a force to the pipe in the direction of flow. Is this force appear from shear strain?

Thank you.

 

[mfig]

It is a viscous flow that gives rise to shear stresses on the pipe.