Fluid-induced instabilities such as whirl and whip are critical self-excited vibration phenomena that challenge the reliability of high-speed rotating machinery. These instabilities arise from the dynamic interaction between the rotor and the circumferential fluid in bearings, seals, or any configuration where two cylinders rotate with fluid in the gap. Whirl typically manifests as a rigid-body forward precession orbit at frequencies near fluid resonance (λΩ) tracking with ma

Steam turbines are subjected to extreme thermal expansion due to high operating temperatures, which can lead to excessive vibration amplitudes and/or elevated bearing metal temperatures. Uneven thermal expansion can cause casing distortion, misalignment, and pipe strain, and in some cases may even lead to rotor–casing rubbing. These conditions may prevent the unit from reaching normal operating states, resulting in penalties within the power generation industry. Thermal (load