Assuming a fixed magnetic field strength (constant B) and an electrode spacing equal to the
fixed diameter of the pipe (constant l = d), the only variable capable of influencing the magnitude
of induced voltage is velocity (v). In our example, v is not the velocity of a wire segment, but rather
the average velocity of the liquid flowstream (v). Since we see that this voltage will be proportional
to average fluid velocity, it must also be proportional to volumetric flow rate, since volumetric flow
rate is also proportional to average fluid velocity