Description: Rotor resonant frequency calculated assuming that the rotor is supported only in the bearings and that the bearings have infinite stiffness; Name: crit speed (dry)
Description: Rotor resonant frequency calculated considering the additional support and damping produced by the action of the pumped fluid within rotor  ; Name: Wet critical speed
Description: average speed given by the stroke length multiplied with the number of complete pumping cycles of the piston, plunger or piston attached to the diaphragm per minute (stroke per minute or pump crank speed); Name: piston velocity