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Single mode flutter of non-rectangular flat panels at low supersonic speeds
Farruh Abdukhakimov, Vasily Vedeneev

Last modified: 2018-04-17

Abstract


Single-mode flutter is a type of the panel flutter occurring at transonic and low supersonic speeds. Transition to instability in the form of single-mode flutter occurs without interaction between natural modes, in contrast to coupled-mode flutter, where coupling between the 1st and 2nd eigenmodes takes place (Dowell, 1974). Single mode flutter cannot be studied by employing aerodynamic piston theory, which is widely used in supersonic aeroelasticity, because this theory is not valid at low supersonic speeds.

Recently, flutter boundaries of rectangular panels were studied (Shitov&Vedeneev, J. Fluids Struct., 2017) by employing full potential flow theory. In thisĀ  paper, we investigate a single-mode flutter of panels of different shapes; namely, trapezoidal and parallelogram plates are considered. The panel is modeled as simply supported elastic plate, the air is considered inviscid and perfect.

To calculate flutter boundaries in the first two eigenmodes, we use the energy method. First, to verify this method for panel flutter calculations, flutter boundaries of rectangular panels are calculated and compared with the full aeroelastic solution (Shitov&Vedeneev, J. Fluids Struct., 2017). Excellent correlation between the two methods is obtained.

Next, trapezoidal and parallelogram panels with different skew angles are considered. We show that flutter boundaries for trapezoidal plates vary slightly in comparison with the rectangular plates. On the contrary, for parallelogram plates even at a small skew angle the aeroelastic stability increases significantly.

The results obtained show that making the aircraft skin panels in the shape of a parallelogram can be an effective method of single-mode flutter suppression at transonic and low supersonic flight speeds.


Keywords


panel flutter; supersonic flow; single mode flutter

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