Extension of Flutter Boundaries Using In-Flight Receptance Data
Final rept. 15 Jun 2010-14 Jan 2013
LIVERPOOL UNIV (UNITED KINGDOM)
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This report describes an experimental study involving the implementation of the method of receptances to control binary flutter in a wind-tunnel aerofoil rig. The aerofoil and its suspension were designed as part of the project. The advantage of the receptance method over conventional state-space approaches is that it is based entirely on frequency response function measurements, so that there is no need to know or to evaluate the system matrices describing structural mass, aeroelastic and structural damping and aeroelastic and structural stiffness. There is no need for model reduction or the estimation of unmeasured states, for example by the use of an observer. It is demonstrated experimentally that a significant increase in the flutter margin can be achieved by separating the frequencies of the heave and pitch modes. In the test carried out so far it has been found that simply increasing the damping, principally of the heave mode, is less effective in increasing the flutter margin than separating the heave and pitch frequencies.