What is whirling of shaft?

Whirling of a shaft refers to the unstable oscillation or vibration that occurs when a rotating shaft's critical speed is approached or exceeded. This phenomenon can result from imbalances, misalignments, or variations in stiffness along the shaft's length. Whirling can lead to excessive vibrations, noise, and potential mechanical failure if not properly managed. Engineers often analyze and mitigate whirling effects through design adjustments, balancing, and proper support systems.