Is Transient Flow Caused by Changes in Velocity's Direction in Pipelines?

[Mikealvarado100]

Hi every one;

Transient [Fluid Transient in Pipelines] is result of changing in momentum and momentum is result of changing in velocity. Velocity is a vector parameter. It means that Velocity's change is due to changing in velocity's quantity or velocity's direction. All discussions about transient Analysis (in books and references) speaks about Transient as result of changing in AMOUNT of velocity not changing in DIRECTION of it.
Assume a pipe with no operations or branches, valves or ... but there is a Bend along the pipe. Changing in velocity's direction makes momentum and therefore it must makes a transient. Am I right or I make mistake and Transient is due to JUST velocity's quantity?

Thanx in advance.

 

[mfig]

I am not sure why you are using the word transient to describe flow in a bend. One could have steady flow in a bend. Yes, a bend will alter the flow direction and must therefore exert a force on the fluid. This doesn't make it a transient flow, however. If the flow field does not change with time, then it is a steady flow regardless of the shape of the pipe.