LAUSR

Panel flutter is an aeroelastic instability of aircraft skin panels, which can lead to a reduction in service life and panel destruction. Despite the existence of many studies related to panel flutter, the influence of the boundary layer on the panel stability has been considered in only a few of them. Up to the present day, most papers on the boundary layer effect consider only a zero-pressure-gradient boundary layer over a flat plate. The only studies of a boundary layer of arbitrary form were conducted in our previous papers (Vedeneev, J. Fluid Mech., vol. 736, 2013, pp. 216–249 and Bondarev & Vedeneev, J. Fluid Mech., vol. 802, 2016, pp. 528–552), where the boundary layer was represented as an inviscid shear layer (the Reynolds number ). In this paper we investigate the problem, taking viscosity into account, at large but finite Reynolds numbers. As before, we assume that the panel length is large and use Kulikovskii’s global instability criterion to analyse the panel eigenmodes and consider two different types of boundary layer profiles: a generalised convex profile and a profile with a generalised inflection point. Results show that viscous perturbations can, in general, have both stabilising and destabilising effects on the system, depending on the velocity and temperature profiles of the boundary layer and on its thickness. However, surprisingly, we prove that if the boundary layer yields a significant growth rate in the inviscid approximation, then the viscosity always produces an even larger growth rate.