Turbine flowmeters use a free-spinning turbine wheel to measure fluid velocity, much like a miniature
windmill installed in the flow stream. The fundamental design goal of a turbine flowmeter is to make
the turbine element as free-spinning as possible, so no torque will be required to sustain the turbine’s
rotation. If this goal is achieved, the turbine blades will achieve a rotating (tip) velocity directly
proportional to the linear velocity of the fluid