Speed profile correction

In any pipe, the fluid velocity is not uniform across the entire cross-section. The shape of this "velocity profile" changes drastically depending on whether the flow is laminar or turbulent. Flow meters, especially those whose operating principle is velocity, are extremely sensitive to these changes, and failure to account for them is one of the main sources of error in industrial measurement.

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Why is Velocity Profile Correction Crucial?

The velocity distribution of a fluid within a pipe is key to understanding a meter's performance.

• In Laminar Flow (Re < 2000): The fluid moves in ordered layers. The velocity profile is parabolic (bullet-like), with maximum velocity in the center of the pipe and zero velocity at the walls.

• In Turbulent Flow (Re > 4000): The movement is chaotic and eddy. This results in a much flatter and more uniform velocity profile across most of the pipe diameter.

 

Flowmeters are typically calibrated for a specific flow profile (usually for developed profiles). When the Reynolds Number of your process changes (due to variations in velocity, viscosity, or temperature), the velocity profile also changes. A meter calibrated for turbulent flow will give an incorrect reading if the flow becomes laminar, and vice versa.

 

Our calculator solves this problem by adjusting the flow reading based on the current flow rate, determined by the Reynolds Number you provide. If you don't know the Reynolds Number, you can calculate it in the following calculator or here.