Flowmeter selection, depending on the working principle of the flowmeter to be used, the physical quantities (process conditions) affecting the flowmeter performance listed below in the Flow terminology must be known.
Factors Affecting Flowmeter Performance:

-Process Fluid ( Liquid, Gas )
-Speed
-Temperature
-Pressure
-Density
-Viscosity
-Sensitivity
-Stability
-Linearity
-Working range

Taking these process conditions into consideration, the flowmeter selection should be made with the most appropriate flowmeter type and modeling.