Description: The ratio of the output variable to the rate of change of the input variable; Name: differential factor
Description: for a derivative element, the quotient of the value of the output variable to the value of the time derivative of the input variable; Name: derivative action coefficient
Description: Speed that characterizes a pump in terms of its speed, flow rate per impeller eye, i.e. total flow for single-flow impeller, half flow for double-flow impeller, at the best efficiency point and head per stage at maximum impeller diameter ; Name: Specific speed