Description: Head observed at inlet area of the installation, corresponding to the sum of the height, pressure head and velocity head  ; Name: Total head at inlet area of the installation
Description: Determined total head at the inlet area of the installation, which corresponds to the sum of geodetic head, pressure head and velocity head; Name: Total head at inlet area of the installation
Description: Speed of rotation at which the frequency of vibration (or its multiples) corresponds to the rotor resonant (lateral or torsional) ; Name: Critical speed