square root Function is required for Orifice Flow Transmitter as the relationship of flow versus pressure is not linear but has a square-root relationship.
The DP flowmeters measure the differential pressure across the constrictions made in the flow channel. This differential pressure measured has nonlinear relation with flow through the pipeline. The square root extractor is used to convert the measured differential pressure into flow rate.
The relationship between flow rate and differential pressure for any fluid-accelerating flow element is non-linear. When plotted on a graph, the relationship between flow rate (Q) and differential pressure (∆P) is quadratic, like one-half of a parabola.