Numerical Studies of Features of Wing Flow in the Buffeting Mode
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cal Studies of Features of Wing Flow in the Buffeting Mode A. V. Voevodina, D. A. Petrova, A. S. Petrova, V. G. Sudakova, and G. G. Sudakova* a
N.E. Zhukovsky Central Aerohydrodynamic Institute, Zhukovsky, Moscow oblast, 140180 Russia *e-mail: [email protected] Received March 13, 2020; revised March 30, 2020; accepted March 30, 2020
Abstract—A numerical method for solving the Reynolds equations for the problem of the flow around a rectangular wing in the buffeting mode is validated and the flow around an infinitely long rectangular wing by an infinite transonic gas stream is calculated. It is shown that, instead of a two-dimensional flow, a flow that is periodic along the lateral coordinate is realized. In addition, there are time-periodic oscillations of the flow along the longitudinal coordinate (buffeting). The presence of the side walls of the pipe deforms this periodic structure and changes the buffeting frequency. The calculation of the flow around the wing–fuselage structure of a mainline aircraft in the transonic buffeting mode shows that the flow oscillations occur in a limited region of the wing both in the longitudinal and transverse directions. Keywords: wing, airplane, buffeting, numerical method. DOI: 10.1134/S1063785020070147
The buffeting of a wing in a transonic flow comprises a flow oscillation caused by the interaction of the shock wave with the separation zone behind the wing. When a rectangular wing of large length is flown around by an infinite flow in this mode, instead of a plane flow, periodic (along the lateral coordinate) mushroomlike structures arise. They were first discovered experimentally [1] in a subsonic separated flow around a wing and then reproduced numerically [2]. The transonic buffeting for a flow around a wing profile has been studied both experimentally [3] and numerically [4, 5]. The buffeting for an airplane model has a much more complex character of oscillations [6]. In [7, 8], it was shown that the beginning of buffeting and the rise of mushroom-like periodic structures are connected with global instability of the flow in the separated flow around a wing. The mechanism of occurrence of self-oscillations of the shock wave was experimentally studied in [9], and the method of suppression was studied in [10]. The main topic of the above works was the study of the main characteristics of the flow in the buffeting mode: the frequency and amplitude of pressure pulsations on the wing surface. In this work, we study the flow around a rectangular wing both in an unlimited stream and in a stream in a perforated working part of a wind tunnel (WT) using a numerical method for solving the Reynolds equations with a turbulent state of the boundary layer. Analysis of the calculation results made it possible to reveal some additional, previously unknown features of the flow: for the case of a WT, separation occurs
only in the central and end wing sections, the medium (in the span) wing sections are flown around without separation, and the amplitude of oscillations of the shock wave depe
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