Computational Modelling of Stochastic Buffeting of Fin-Like Structures

This work proposes a novel computational model for estimating stochastic buffeting loads on an aircraft fin-like structure. Fin buffeting refers to the response of an aircraft fin to the aerodynamic excitation by separated flow from the upstream components like wing, foreplane, fuselage, etc. Depending on flight conditions and aircraft configurations, the buffeting response can be significantly large, leading to structural failure due to fatigue. Through this work, a thorough survey of the sources of fin buffeting has been performed, and each source is identified to have distinct spectral characteristics. Using available experimental data of power spectra for different buffeting sources, temporally consistent velocity fields upstream of the fin have been reconstructed using the Spectral Representation Method (SRM). In this study, we have proposed a novel implementation of the stochastic input velocity, modelled through SRM as a random process with a stipulated correlation, as an inlet boundary condition in a finite volume method-based Navier–Stokes solver. A computational study using the novel boundary condition has been performed on a symmetric NACA airfoil located in the wake of an idealised delta wing to estimate the buffeting loads. The power spectra for the lift coefficient obtained using the proposed method have been compared with Liepmann’s analytical model for buffeting.