An aircraft engine rotor system is provided with a squeeze film damper mechanism that allows axial flow of lubricant in a squeeze film region without creating a gross circumferential distortion of pressure around the damper journal. The outer race of a rolling-element bearing assembly which assembly is disposed in a journal bearing enclosure, is provided with a number of encircling annular slots, these slots providing space for reception of a spaced pair of serrated rings which are fixed to an inner wall surface of the journal bearing enclosure, the serrated peripheries of the rings being in contact with the bearing journal enclosure inner wall space. Oil enters the squeeze film region through the serrations in one of the rings and outflows through those in the other ring. The outer race of the rolling-element bearing assembly preferably is pinned or otherwise prevented from rotating so that it will orbit in translating movement in the same manner as the rotor shaft which is received in the inner race companion to the outer race. During orbiting movement of the assembly, the fixed position rings are unaffected by that movement since the outer race continuous slots are deep enough to allow the assembly to orbitally move relative to the fixed rings (alternatively, the deep slots could be in the bearing assembly with the rings fixed to the journal). The rings can have less clearance in the slots than conventional rings and this contributes to maintanance of large pressures in the squeeze film region since oil flow from one end of the squeeze film region to the other is not around the rings whereat pressure distortions can occur, but rather through the serrations.
