Assessment of Geometry Reconstruction Techniques for the Simulation of Non-Classical Aileron Buzz

Abstract

A computational study of non-classical aileron buzz is presented, which focuses on computational grid details for accurate simulations of this type of nonlinear transonic phenomenon. The analysis points out that mesh refinement is crucial to obtain reliable results and that the choice between a smoothed and non-smoothed geometry has an influence on the system response, both quantitatively and qualitatively. As a matter of fact, grid details affect the simulation of shock dynamics, which is the driving mechanism for non-classical aileron buzz

Multiple input describing function analysis of non-classical aileron buzz

“…The reliability of the presented numerical model and problem setup has been extensively established by earlier research works (Romanelli et al 2010, Fusi et al 2012, Biganzoli and Quaranta 2009 through various tests and by tackling a set of realistic static and dynamic aeroelastic problems. A C-mesh with hexahedral elements is used to model the flow.…”

“…It extends ±10 chords both chordwise and in the airfoil thickness direction. A convergence study reported in (Fusi et al 2012) showed that with about 50000 elements it is possible to reach a sufficient degree of spatial convergence.…”

“…For the asymmetrical airfoil under consideration, the initial condition for the equation of motion is a perturbation provided by the initial steady unbalanced aerodynamic moment acting on the aileron while it is at zero-deflection angle. The aeroelastic interface is created exploiting the fact that the airfoil and the flap are rigid (Fusi et al 2012). Hence, at each instant of time the aileron deflection angle is calculated and the displacements of the boundary cells surrounding the aileron are related to the aileron deflection angle through a rotation operator.…”

“…with an appropriate structural model have proven to be accurate enough to analyze nonlinearities involved in the unsteady aerodynamics of aileron buzz (Steger and Bailey 1980, Fuglsang et al 1992, Bendiksen 1993, Pak and Baker 2001, Fusi et al 2012, Forestieri et al 2011, Gao et al 2015. However, standard CFD models that include the relevant aerodynamic nonlinearities are too expensive, especially if developed for parametric design analysis to be performed in the preliminary design phases of aircraft development.…”