How does an annubar water flow test work?

An annubar water flow test measures flow rate using a flow sensor that combines a flow element and a differential pressure measurement. The annubar consists of a tube with multiple pressure taps, which measure the pressure difference between the upstream and downstream sides of the flow element. This pressure difference is used to calculate the flow velocity based on Bernoulli's principle. The flow rate can then be determined by multiplying the velocity by the cross-sectional area of the pipe.