The method of measuring flow indirectly by observing the change in pressure is known as what?

The method of measuring flow indirectly by observing the change in pressure is known as the pressure differential method. This approach involves utilizing devices like orifice plates, venturi meters, or nozzles to create a pressure drop as fluid flows through them. The difference in pressure before and after the restriction is measured, and this difference can be correlated to the flow rate according to Bernoulli's principle.

The underlying concept is that as fluid velocity increases through a restriction, the pressure decreases, and by measuring this pressure differential, one can derive the flow rate. This method is widely used in various applications due to its reliability and the minimal maintenance required once installed.

Other options do not directly refer to this concept; for instance, velocity measurement focuses specifically on the speed of the fluid rather than the pressure change, viscosity assessment pertains to the fluid's thickness and resistance to flow rather than flow rate measurement, and flow restriction analysis could imply evaluating the impact of an obstruction instead of measuring the flow indirectly through pressure changes.