Nicholas F. Giannelis, Gareth A. Vio

DOI Number: N/A

Conference number: IFASD-2017-074

Within a narrow band of the transonic flight regime, shock-wave/boundary layer interactions yield large amplitude, self-sustained shock oscillations. When this transonic buffet instability interacts with a forced or freely oscillating structure, frequency lock-in between the aerodynamic and structural modes can occur, resulting in large amplitude limit cycle oscillations of the structure. In this study, the lock-in phenomenon is investigated by means of Reynolds-Averaged Navier-Stokes simulations. Harmonically driven pitching simulations are performed for a range of driving frequencies and amplitudes for the supercritical OAT15A aerofoil section. The results show that for a band of driving frequencies near the buffet, frequency synchronisation develops for sufficient driving amplitudes. The flow topology within the lockin regions differs for driving frequencies above and below the buffet. This is attributed to a phase reversal of the aerodynamic coefficients as the excitation frequency passes through the fundamental flow frequency. Analysis of the gain and phase relationships of the aerodynamic coefficients supports the findings of prior studies, where the lock-in phenomenon is related to bounded single degree-of-freedom flutter.

Read the full paper here

In Categories: 1.Events, Computational Aeroelasticity, IFASD 2017
Email
Print
LinkedIn
The paper above was part of  proceedings of a CEAS event and as such the author has signed a publication agreement to have their paper published in the repository. In the case this paper is found somewhere else CEAS always links to the other source.  CEAS takes great care in making the correct content available to the reader. If any mistakes are found  in the listings please contact us directly at papers@aerospacerepository.org and we will correct the listing promptly.  CEAS cannot be held liable either for mistakes in editorial or technical aspects, nor for omissions, nor for the correctness of the content. In particular, CEAS does not guarantee completeness or correctness of information contained in external websites which can be accessed via links from CEAS’s websites. Despite accurate research on the content of such linked external websites, CEAS cannot be held liable for their content. Only the content providers of such external sites are liable for their content. Should you notice any mistake in technical or editorial aspects of the CEAS site, please do not hesitate to inform us.