Electromagnetic Flowmeter:

The electromagnetic flowmeter is same in principle to the generator. A rotor of the generator is exchanged through a pipe placed among the poles of a magnet so in which the flow of the fluid in the pipe is general to the magnetic field. As the fluid flows by this magnetic field, an electromotive force is induced in it which will be mutually common (perpendicular) to both the magnetic field and the motion of the fluid. That electromotive force might be measured along with the aid of electrodes attached to the pipe and connected to a galvanometer or an equivalent.  For a provided magnetic field, the induced voltage will be proportional to the average velocity of the fluid. Thus, the fluid should have a few degree of electrical conductivity.