Aircraft engine with squeeze film damper

An aircraft engine, comprising:

• a shaft rotatable about a central axis;
• a bearing housing extending around the shaft, the bearing housing defining a bearing cavity;
• a bearing located within the bearing cavity, the bearing rotatably supporting the shaft;
• a squeeze film damper having an annulus defined radially between the bearing and the bearing housing, the annulus receiving a damping fluid, the squeeze film damper operable in a selected one of two distinct regimes consisting of:
• a first regime in which a speed of the damping fluid in the annulus is less than a speed of sound in the damping fluid;
• and
• a second regime in which the speed of the damping fluid in the annulus is greater than the speed of sound in the damping fluid;
• and
• a controller having one or more data processors and a non-transitory machine-readable memory storing instructions executable by the one or more data processors and configured to cause the one or more data processors to:
• determine whether an amplitude of vibrations of the shaft is above or below an amplitude threshold;
• in response to determining that the amplitude of the vibrations of the shaft is below the amplitude threshold, operate the squeeze film damper in the first regime;
• and
• in response to determining that the amplitude of the vibrations of the shaft is above the amplitude threshold, operate the squeeze film damper in the second regime.