Resolvent analysis on the origin of two-dimensional transonic buffet

Abstract

Resolvent analysis is performed to identify the origin of two-dimensional transonic buffet over an airfoil. The base flow for the resolvent analysis is the time-averaged flow over a NACA 0012 airfoil at a chord-based Reynolds number of 2000 and a free-stream Mach number of 0.85. We reveal that the mechanism of buffet is buried underneath the global low-Reynolds-number flow physics. At this low Reynolds number, the dominant flow feature is the von Karman shedding. However, we show that with the appropriate forcing input, buffet can appear even at a Reynolds number that is much lower than what is traditionally associated with transonic buffet. The source of buffet is identified to be at the shock foot from the windowed resolvent analysis, which is validated by companion simulations using sustained forcing inputs based on resolvent modes. We also comment on the role of perturbations in the vicinity of the trailing edge. The present study not only provides insights on the origin of buffet but also serves a building block for low-Reynolds-number compressible aerodynamics in light of the growing interests in Martian flights.

arXiv comment11 pages, 7 figures

References in corpus (3)

• A critical layer model for turbulent pipe flow
• Spectral analysis of jet turbulence
• Resolvent-analysis-based design of airfoil separation control

Cited by in corpus (6)

• Wavelet-based resolvent analysis of non-stationary flows
• A novel convergence enhancement method based on Online Dimension Reduction Optimization
• Biglobal resolvent analysis of separated flow over a NACA0012 airfoil
• Resolvent-based estimation and control of a laminar airfoil wake
• Variational mode decomposition analysis of the relationship between low-frequency shock-wave oscillations and buffet cells
• Transient growth and nonlinear breakdown of wavelet-based resolvent modes in turbulent channel flow