Buffet boundary estimation using a harmonic balance method

A B S T R A C T In this work, the application of the harmonic balance technique is demonstrated for transonic buffet cases. The harmonic balance method represents an alternative to time-marching simulations that are expensive for complex flow cases. Here this technique is applied on different test cases with inherently unsteady flows, i.e. two different aerofoil configurations undergoing transonic buffet. A gradient-based, variable time period method is used to estimate the frequency of oscillation for flows where it is not know a priori. The reduced computer costs with respect to time marching simulations allowed to embed the harmonic balance computation in a simple procedure for the buffet boundary estimation. The aim is to improve the prediction coming from criteria based on the results of steady computations, still popular in industry.(c) 2022 The Authors. Published by Elsevier Masson SAS. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).