Vibration analysis of a cracked rotor surrounded by viscous liquid

Crack detection in, and vibration characteristics of, a shaft with two open cracks rotating in a fluid medium are studied in this paper. The influence coefficient method is used to find the fundamental frequency of the cracked shaft. The frequency contours with respect to crack depths and locations are used to identify cracks. The effect of fluid on the cracked rotor is analyzed with the help of Navier-Stokes equations. The dynamic response of the rotating cracked shaft is compared with that of an uncracked one, and it is found that, when the cracked rotor rotates in a viscous fluid, there is change in the critical speeds and amplitudes of vibration.