Vibration Characteristics of Hydrodynamic Fluid Film Pocket Journal Bearings

Table 2

Damped natural frequencies of a rotor supported by elliptic or pocket bearings ((1) refers to type 1, etc.).

Speed (rpm)	1000	2000	3000	4000	5000
Elliptic	Real, Imag (rad/s)
Mode 1	−19.91,137.5	−11.17,143.9	−7.588,150.4	−5.047,156.1	−3.323,160.8
Mode 2	−4.064,211.8	−5.900,207.7	−6.266,204.2	−5.913,201.6	−5.291,199.6
Mode 3	−129.3,217.4	−89.73,261.5	−84.35,288.3	−79.77,317.3	−70.84,344.6
Pocket	Real, Imag (rad/s)
Mode 1
(1)	−27.05,192.6	−19.47,183.2	−10.63,184.8	−5.012,189.2	−1.620,193.4
(2)	−30.75,186.0	−23.41,175.1	−15.76,177.6	−9.796,182.3	−6.021,186.6
Mode 2
(1)	−3.379,212.6	−4.965,209.7	−5.133,207.6	−4.768,206.3	−4.255,205.4
(2)	−3.633,212.0	−4.647,208.7	−4.249,206.8	−3.419,205.9	−2.527,205.6
Mode 3
(1)	−162.5,75.30	−246.2,140.1	−300.0,189.1	−352.9,237.0	−418.2,293.1
(2)	−201.1,48.79	−331.0,79.78	−390.9,114.1	−473.7,166.2	−566.0,241.0
Mode 4
(1)	−85.34,57.67	−140.8,121.7	−194.9,206.5	−223.7,315.3	−202.6,425.3
(2)	−111.7,29.36	−196.7,118.1	−258.1,265.9	−212.5,394.2	−155.1,462.0