Average (Bulk) Velocity

In most of the fluid flow problems, rather than determining precise velocities at various locations in the similar flow cross-section, it is enough to permit a single average velocity to symbolize the velocity of all fluid at that point in the pipe. This is pretty easy for turbulent flow as the velocity profile is flat over the majority of the pipe cross-section. It is reasonable to suppose that the average velocity is similar as the velocity at the center of the pipe.

When the flow regime is laminar (i.e., the velocity profile is parabolic), the problem still exists of trying to symbolize the "average" velocity at any given cross-section as an average value is employed in the fluid flow equations. Technically, this is completed by means of integral calculus. Practically, the student must use an average value which is half of the center line value.