The relation between different types of transonic buffet

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• Dr. Pradeep Moise (University of Southampton)
• Friday 11 February 2022, 12:30-13:30
• CUED, LT6.

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Transonic buffet (TB) generally refers to the self-sustained, periodic oscillations of shock waves that can occur on wings in the transonic regime. It can cause strong variations in lift and structural vibrations, thus limiting the flight envelope of aircraft. Based on the characteristics of the boundary layer at the shock foot, TB has been further classified as laminar or turbulent buffet. Additionally, based on whether shock waves exist on either side of the aerofoil or only on the suction side, it has been classified as Type I or Type II buffet. Distinct physical mechanisms have been proposed previously to govern each of these TB types. To investigate the relation between these TB types, we have performed Large-Eddy simulations of transonic flow over infinite wing sections for a wide range of flow parameters and successfully simulated each type. Using a spectral proper orthogonal decomposition (SPOD), we have shown that these flows are dominated by two coherent flow features – a low-frequency buffet mode and high-frequency wake modes. A low-rank reconstruction based only on the former SPOD mode allowed to tease out TB characteristics and indicates that the mechanisms governing different TB types might be the same. Further exploration of the parametric space also suggests that shock waves might not be essential for “transonic” buffet to occur. These results shed light on the mechanisms underlying TB and could potentially aid in developing strategies towards mitigating it and extending the flight envelopes of aircraft.

This talk is part of the Fluids Group Seminar (CUED) series.

This talk is included in these lists:

• Acoustics Lab Seminars
• CUED, LT6
• Engineering Department Acoustics/Combustion Student seminars
• Fluids Group Seminar (CUED)

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