A theoretical model is developed for predicting the dynamic behaviour
and stability of a rotating shaft immersed in both a concentric or ecc
entric fluid annulus. Of specific concern here are geometries presenti
ng a moderate flow-confinement, for which scarce results exist. Theore
tical results show that moderate gap configurations lead to quite dist
inct flow forces, when compared to typical bearing configurations. Als
o, the annulus eccentricity is shown to be a very important parameter,
controlling rotor dynamics and stability. In a companion paper (Part
2), experimental results are reported and favourably compared with the
present theory. (C) 1996 Academic Press Limited