ESDU 95023:2010

INTRODUCTION

ESDUpac A9523 is a FORTRAN 77 computer program for determining
the response to imbalance and the onset of oil-whip instability of
a simple flexible rotor (see Section 1.3) supported in cylindrical
axial groove hydrodynamic journal bearings.

The program is able to determine the out-of-balance response of
the rotor for either constant rotational speed or constant
acceleration with or without speed dependent external loading. A
complete working cycle of the rotor consisting of a run-up to
operational speed, followed by a period of constant speed and then
a coast-down can be simulated. During a simulation, selected
parameters, such as deflections and bearing forces, can be recorded
in a form suitable for plotting.

For comparison with the dynamic response, the program also
allows the steady-state imbalance response and the nominal
threshold speed for oil-whip instability to be determined.

The program will be of use in assessing the suitability of
cylindrical axial groove journal bearings for supporting a rotor
and for determining the effect of making design changes to the
bearings or the rotor^†. The program will also be of use
in interpreting measurements made on operating rotor systems when
trouble shooting, for example.

^† ESDUpacs A9305 and A9306 are computer programs for
designing axial groove journal bearings. The use of these programs
is explained in ESDU 93005 and ESDU 93006 (see References 1 and 2).
The background to the design methods used can be found in ESDU
84031, ESDU 85028 and ESDU 86008 (see References 3, 4 and 5).

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