Fuselage Excitation During Cruise Flight Conditions: A New CFD Based Pressure Point Spectra Model

Abstract

In the last fifty years many semi-empirical models to predict surface pressure fluctuations beneath turbulent boundary layers (TBL) have been developed for a large variety of test conditions. Nowadays, the relevance of the TBL as a source of cabin interior noise is steadily increasing, due to quieter aircraft engines. The accuracy of various publicly available semi-empirical pressure point spectra models has been investigated on several regions of DLR’s Airbus A320, Advanced Technology Research Aircraft (ATRA). A large validation database was used, involving in-flight measurements at different flight levels (FL) and Mach numbers, employing two different sensor types. Even the most suitable modelling approaches are not generally applicable to all relevant positions at the fuselage. Particularly in regions with high turbulence kinetic energy measured auto-spectra cannot be reproduced with sufficient accuracy. This indicates the need for more universally applicable computational fluid dynamics (CFD)-based surface pressure prediction methods. Therefore, a new model, based on CFD data, which is confirmed with flight test data, is introduced in this paper. The CFD data is calculated with DLR’s TAU code, using a new Reynolds stress turbulence model (RSMg).