Similarities Between Cellular Patterns Occurring in Transonic Buffet and Subsonic Stall

Global instability of wing shock-buffet onset

“…The data taken from Crouch et al (2019) have been rescaled with respect to the reference velocity normal to the leading edge to be consistent with the definition used in Paladini et al (2019a). It appears that our relevant triglobal modes discretise the continuous medium-wavelength band of modes, first presented by Crouch et al (2019), albeit necessary secondary geometric features of the finite wing (such as taper and twist), suspected to modify the development of those modes (Plante et al 2019b). Nonetheless, triglobal stability analysis of such infinite wings benefits clearer interpretation of biglobal studies and their relation to a finite wing with complex geometry (He & Timme 2020).…”

“…In the three-dimensional case, Iovnovich & Raveh (2015) pursued the categorisation of the three-dimensionality of wing buffet by progressively building up the geometric complexity. Similarly, relying on a basic Global instability of wing shock-buffet onset 885 A37-3 infinite-wing set-up, the isolated impact of sweep angle has been studied using modal analysis (Crouch, Garbaruk & Strelet 2019;Paladini et al 2019a;Plante et al 2019a) and time-marching unsteady RANS (Plante, Dandois & Laurendeau 2019b). Scale-resolving detached-eddy simulation on the other hand has been applied for finite-wing shock-buffet flow by Brunet & Deck (2008), Sartor & Timme (2017) and Ohmichi, Ishida & Hashimoto (2018), supporting the above mentioned spanwise propagation of buffet cells.…”

Link between subsonic stall and transonic buffet on swept and unswept wings: from global stability analysis to nonlinear dynamics

“…A fit coefficient of 0.7 is found for the buffet cells and 0.8 for the stall cells. More details are provided in Plante et al (2019b). This relation between the sweep angle and the convection speed of the buffet cells is further analysed using stability analyses in § 4 for the stall and buffet conditions.…”

“…They observed buffet cells and an effect of the sweep angle on the buffet amplitude and frequency. Previous work by the authors (Plante et al 2019b) investigated infinite swept wings closed by periodic boundary conditions. Such simulations produced much more regular buffet cells and showed that buffet cells occur without any 3-D disturbance from the physical set-up, thus making this phenomenon a candidate for an explanation based on global stability analysis.…”

“…Liu & Nishino (2018) studied the unsteady behaviour of stall cells over a NACA0012 at a Reynolds number of and . Previous work by the authors (Plante, Dandois & Laurendeau 2019 b ), based on URANS simulations of an NACA4412 aerofoil at Reynolds , showed the convection of the stall cells in the spanwise direction when the wing is swept. To the authors’ knowledge this is the first analysis of the stall cells phenomenon on swept wings.…”