NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The effect of circumferential aerodynamic detuning on coupled bending-torsion unstalled supersonic flutterA mathematical model developed to predict the enhanced coupled bending-torsion unstalled supersonic flutter stability due to alternate circumferential spacing aerodynamic detuning of a turbomachine rotor. The translational and torsional unsteady aerodynamic coefficients are developed in terms of influence coefficients, with the coupled bending-torsion stability analysis developed by considering the coupled equations of this aerodynamic detuning on coupled bending-torsion unstalled supersonic flutter as well as the verification of the modeling are then demonstrated by considering an unstable 12 bladed rotor, with Verdon's uniformly spaced Cascade B flow geometry as a baseline. However, with the elastic axis and center of gravity at 60 percent of the chord, this type of aerodynamic detuning has a minimal effect on stability. For both uniform and nonuniform circumferentially space rotors, a single degree of freedom torsion mode analysis was shown to be appropriate for values of the bending-torsion natural frequency ratio lower than 0.6 and higher 1.2. When the elastic axis and center of gravity are not coincident, the effect of detuning on cascade stability was found to be very sensitive to the location of the center of gravity with respect to the elastic axis. In addition, it was determined that when the center of gravity was forward of an elastic axis located at midchord, a single degree of freedom torsion model did not accurately predict cascade stability.
Document ID
19870038122
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hoyniak, D.
(NASA Lewis Research Center Cleveland, OH, United States)
Fleeter, S.
(Purdue University West Lafayette, IN, United States)
Date Acquired
August 13, 2013
Publication Date
October 1, 1986
Publication Information
Publication: ASME, Transactions, Journal of Turbomachinery
Volume: 108
ISSN: 0889-504X
Subject Category
Aircraft Propulsion And Power
Report/Patent Number
ASME PAPER 86-GT-100
Accession Number
87A25396
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available