Another name for the rotameter flow meter is _____________.

The rotameter flow meter is commonly referred to as a variable orifice flow meter. This is because it operates by utilizing a tapered tube that allows fluid to flow through an orifice that changes in size based on the flow rate. As the flow increases, the fluid pushes a float upward within the tapered tube, and the position of the float indicates the flow rate. The more fluid that flows through, the larger the effective orifice becomes as the float moves higher, thus allowing for a direct measurement of flow based on the variable size of the orifice.

The term "rotameter" specifically denotes this design, which relies on variable flow conditions in a transparent tube to visually indicate flow rates. This functionality is distinct from the other terms listed, which refer to different types of devices or mechanisms that do not serve the same purpose or operate in the same manner.