Which of the following devices is not part of Closed Channel Flow Measurements?

In the context of closed channel flow measurements, the primary objective is to accurately measure the flow of liquids, typically wastewater, within a sealed system. Closed channels, like pipes, do not allow for flow measurement via surface flow elements like weirs, which are intended for open channel flow.

Acoustic devices and magnetic flow meters are both effective tools used in closed channel flow measurements. Acoustic devices utilize sound waves to determine the velocity of the fluid, while magnetic flow meters measure the flow based on the principles of electromagnetic induction, both functioning well regardless of changes in pressure or density as long as the fluid is conductive.

Rotameters are also applicable in certain closed channel configurations to measure the flow rate of fluids by using a float that moves up and down in a tapered tube. However, they are generally used in lower pressure systems and might not be ideal for all closed systems.

In contrast, weirs are structures placed in open channels that allow for the measurement of flow over the top of the weir. They rely on the principles of fluid dynamics in an open environment to function, which is not suitable for closed channels where the flow is contained within pipes, hence making weirs irrelevant in the context of closed channel flow measurements.