university of florida thesis or dissertation formatting template

Denegri 23 explains the flutter flight test profile included herein. Testing typically begins at
10,000 feet mean-sea-level (MSL) altitude and a low Mach number and progresses in increments
beyond the desired carriage envelope. This progression is then repeated at 5,000 and 2,000 feet
MSL. At these altitudes, full data sets are obtained which consist of collection of random
atmospheric excitation data, constant frequency excitation of the flaperon control surface, and
elevated load factor maneuver. If needed, test points are accomplished at higher altitudes in order
to better define the envelope. An illustration of the testing envelope is provided in Figure 2-5.
Random atmospheric excitation data is collected while the aircraft is flown in a straight-
and-level, trimmed condition. If random atmospheric turbulence does not sufficiently excite the
aircraft structure, an FES sweep is performed. The data are analyzed real-time in the control
room using spectral analysis software and the frequency content is evaluated to determine the
presence of any critical modes. The FES is then tuned to oscillate the flaperon at the critical
frequency. A symmetrically-loaded turn of incrementally increasing load factor is also performed
to determine the effects of increased load factor and angle of attack on the flutter characteristics.
A symmetric pull-up maneuver is sometimes used for test points during dive maneuvers.
Denegri 13 observed that in most LCO flight tests, the free vibration modes that make up the
predicted flutter mechanism show the largest deflections at the wing-tip. These modes are
antisymmetric (with both inboard and outboard wing motion) and the resulting motion at the
wing-tips has both bending and twisting components with little flexible motion at the wing-root.
These modes impart a rolling moment to the aircraft fuselage, thus establishing an energy
transfer path for antisymmetric LCO. Based on these observations, this dissertation will attempt
to recreate these wing-tip motions via computational fluid dynamics (CFD) analyses.
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