Hadrien J. Mamelle, Gabriel Broux, Eric C. Garrigues
DOI Number: N/A
Conference number: IFASD-2017-124
The flutter behavior of the innovative U-tail aircraft studied by Dassault Aviation is significantly influenced by specific aerodynamic phenomena which are computationally challenging to predict. This article presents the effect of the aerodynamic interactions between the U-tail surfaces on the flutter behavior as well as the corner flow aerodynamic aspects arising in the area where the tail surfaces intersect. A fruitful wind tunnel tests campaign has been successfully conducted in ONERA S2MA pressurized wind tunnel on a half U-tail mock-up which has been heavily instrumented to gather flutter and aerodynamic data in subsonic and transonic domains. Structural, aerodynamic and flutter correlations between experimental and numerical results are presented and point out that relevant and valuable data have been recorded for numerical tools assessment. Emphasis is put on the remarkable mockup structural behavior thanks to which excellent flutter onsets repeatability has been observed. The mock-up dynamic behavior is accurately modelled by a tuned Finite Element model which modal behavior is used to compute flutter results presented in this paper. Experimental flutter curves creation and flutter mode shape extraction from the measured data are presented and demonstrate that the targeted bending-torsion flutter mechanism has indeed been measured. These experimental and numerical results give good confidence in the suitability of this comprehensive experimental database in evaluating the validity domain of numerical tools and in calibrating aerodynamic prediction tools. In the end an industrial computational strategy to accurately compute the intersecting surfaces flutter behavior and aerodynamics should be available to study conceptual aircraft configurations like the U-tail.