h0: A high axial bearing stiffness,
self-aligning capability and the minimal flow is obtained
with small film thickness. The minimal value of the film
thickness is limited by bearing deflections and flatness of the
bearing surface and is usually related to the bearing size.
δ, h2: The volume of the pocket must be as
small as possible to make the bearing less sensitive to
instability. The pocket however is needed to get a smooth
pressure distribution in the circumference and secondly to
realize simple orifice compensation. The pressure
distribution in the groove is assumed to be homogenous which
is a good approximation for a large groove depth. Numerical
calculations are required to calculate the effect of the
pressure drop in shallow grooves.
The restrictor can become inherent with shallow grooves and
Ac must therefore be checked. The pressure drop over passage
A1 of the simple orifice restrictor is more than four times
higher than that over the annulus area A2 when Ac>1 (Fig
12.2 of the book).