Performance prediction of squeeze film bearing dampers depends largely on the extent and type of cavitation taking place within the squeeze film land. The investigation described here was intended to probe the phenomenon of cavitation in squeeze film dampers and provide some insight, answers, and possible explanations for some of the measurements and behavior which are generally not predicted by classical lubrication theory. High speed photography was utilized to verify the occurance of vapor cavitation, as well as that of gaseous cavitation which later developed into a two phase homogeneous mixture of oil and air when the test rig was operated at higher speeds. Video recordings at slower speeds showed a blurred image of the trace the bubbles moved through and thus provided a visual record of the flow reversal and oscillatory motion in the squeeze film damper.Presented at the 43rd Annual Meeting in Cleveland, Ohio May 9–12, 1988