Erratum: Global instability in the onset of transonic-wing buffet (J. Fluid Mech. (2019) 881 (3-22) DOI: 10.1017/jfm.2019.748)

Abstract

The original paper Crouch, Garbaruk & Strelets (2019) identified three global modes of instability associated with swept-wing buffet: long-wavelength modes, intermediate-wavelength modes, and short-wavelength modes. Following that earlier investigation, an independent study using an alternative formulation for the stability equations (Paladini et al. 2019) was not able to reproduce the growth characteristics for the short-wavelength modes. Meanwhile, we also applied a new formulation based on a fully three-dimensional eigenfunction to independently assess the initial results. In the course of this work, an error was identified in the numerical results by Crouch et al. (2019) associated with a term in the eddy-viscosity equation. The error (here corrected) had minimal impact on the frequencies but a larger impact on the growth rates, with the error increasing with the spanwise wave number. While the long-wavelength and intermediate-wavelength growth rates are weakly altered, the short-wavelength growth rates are significantly modified. Figures 3, 4, 6, and 7, and figures 10 through 14 are replotted here based on the original formulation by Crouch et al. (2019) with corrected numerics. The discussion and overall findings by Crouch et al. (2019) remain unchanged, with the exception that the peak growth rate for the short-wavelength modes occurs at β ≈ 25 as opposed to β ≈ 45, and the short-wavelength onset of instability is now consistently supercritical to the long-wavelength oscillatory modes. The overall agreement between the stability analysis and the URANS is slightly improved. The new figures provide a quantitative correction to the growth rates and stability boundaries, but are qualitatively the same.