The Presence of a Revolution Load and Its Rotational Speed of Half the Speed of the Journal Are Necessary Conditions for the Half-Frequency Whirl of Radial Bearings

In the radial sliding bearing lubrication theory, the half-frequency whirl phenomena are commonly
introduced. However, the correlation of the half-frequency whirl theory with the measured resonance
phenomenon is low. This paper studies the establishment of the half-frequency whirl theory and finds
that while researchers are aware of the half-frequency whirl, they disregard the necessary conditions
of its occurrence. If there is no revolution load, then the half-frequency whirl does not comply with the
principle of minimum potential energy. If it does not conform to the principle of minimum energy
dissipation, then the half-frequency whirl does not exist. Only when the revolution load exists and its
speed is half the speed of the journal will the half frequency whirl occur. Engineering oil whip results
from the vibration of the rotating system. A precise radial sliding bearing lubrication theory should use
cylindrical coordinates, consider the compressibility of the liquid, and consider the surface shear
stress in the journal bearing capacity calculations.