Publications

Version: 1.0 Approved

LDO-ID 2022PUB00061

Title Evolution in Buffet Loads Determination for Tilt Rotor

Abstract

The purpose of this work is to present and describe the state-of-the-art of the validated buffet loads determination methodology developed by Leonardo Helicopters, with particular attention to the aerodynamic modelling and the associated structural loads calculation. The modern Computational Fluid Dynamics, validated by Wind Tunnel testing, is the first major topic addressed in the paper: CFD simulations are performed with ANSYS Fluent commercial software, using a pressure-based coupled URANS scheme. A detailed grid sensitivity analysis linked with turbulence model investigation has been conducted with focus on obtaining the most accurate and validated results, balancing the computational costs. Once the proper settings are defined, simulations are run for different potential buffet conditions with the purpose to characterize the oscillatory pressure distributions generated by the wing stall. The structural loads calculation is the next part of this process, with a focus on the interface with the aerodynamic input and the necessary statistical evaluations and analyses, in order to predict safe loads starting from their deterministic frequency spectra, Power Spectral Densities, average, Root Mean Square and oscillations. Buffet usually needs to be dealt with as a random phenomenon, which is robust and repeatable only in terms of statistic quantities, and, in order to estimate the maximum likely values, a probabilistic approach is used to calculate a reasonable safety factor. The last topic is the analysis of actual flight data in compatible high angle of attack conditions in order to substantiate both the load analysis deterministic results and the statistical approach to predict peak values for aircraft design

Authors Trezzini, Alberto Angelo; Dall'aglio, Maria Ludovica; Donini, Nicola; Cassinelli, Carlo

Type Paper for Seminar/Symposium/Conference

Media Vertical Flight Society - Annual Forum & Technology Display (10-12 May 2022, Fort Worth, TX, USA)

Web site

https://vtol.org/annual-forum/forum-78-proceedings?paperSort=techSession#Dynamics%20I

Anno 2022

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