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Romano D.G.,Piaggio | Alfredsson P.H.,KTH Royal Institute of Technology | Hanifi A.,KTH Royal Institute of Technology | Hanifi A.,Swedish Defence Research Agency | And 7 more authors.
Applied Mechanics and Materials

This document explains in its first part the design procedure adopted to design the contoured sidewalls of a swept-wing airfoil section mounted in a wind tunnel in order to satisfy the infinite swept-wing approximation. In the second part, the experimental set-up is described as well as the first results of the experimental campaign. The sidewalls are shown to play their role properly and satisfactorily provide the infinite swept-wing conditions required for subsequent investigations of the most important vortex receptivity mechanisms responsible for excitation of crossflow and Tollmien-Schlichting instability modes in the airfoil boundary layer. © (2013) Trans Tech Publications, Switzerland. Source

Dimino I.,The Italian Aerospace Research Center | Concilio A.,The Italian Aerospace Research Center | Pecora R.,University of Naples Federico II
24th AIAA/AHS Adaptive Structures Conference

In morphing structures, actuation is a key system for general aircraft-level functions. Similarly to the demonstration of safety compliance applied to aircraft control surfaces, novel functions resulting from the integration of a morphing device (ATED), imposes a detailed examination of the associated risks. Because of the concept novelty, literature references for a safe design of a morphing trailing edge device are hard to be found. The safety-driven design of ATED requires a thorough examination of the potential hazards resulting from operational faults involving either the actuation chain, such as jamming, or the external interfaces, such as loss of power supplies and control lanes. In this work, a study of ATED functions is qualitatively performed at both subsystem and aircraft levels to identify potential design faults, maintenance and crew faults, as well as external environment risks. The severity of the hazard effects is determined and placed in specific classes, indicative of the maximum tolerable probability of occurrence for a specific event, resulting in safety design objectives. A fault tree is finally produced to evaluate the impact of actuation kinematics on specific aspects of ATED morphing operation and reliability. © 2016, American Institute of Aeronautics and Astronautics Inc, AIAA, All rights reserved. Source

Dimino I.,The Italian Aerospace Research Center | Concilio A.,The Italian Aerospace Research Center | Schueller M.,Fraunhofer Institute for Electronic Nano Systems | Gratias A.,Fraunhofer Institute for Electronic Nano Systems
Proceedings of SPIE - The International Society for Optical Engineering

A key technology to enable morphing aircraft for enhanced aerodynamic performance is the design of an adaptive control system able to emulate target structural shapes. This paper presents an approach to control the shape of a morphing wing by employing internal, integrated actuators acting on the trailing edge. The adaptive-wing concept employs active ribs, driven by servo actuators, controlled in turn by a dedicated algorithm aimed at shaping the wing cross section, according to a pre-defined geometry. The morphing control platform is presented and a suitable control algorithm is implemented in a dedicated routine for real-time simulations. The work is organized as follows. A finite element model of the uncontrolled, non-actuated structure is used to obtain the plant model for actuator torque and displacement control. After having characterized and simulated pure rotary actuator behavior over the structure, selected target wing shapes corresponding to rigid trailing edge rotations are achieved through both open-loop and closed-loop control logics. © 2013 SPIE. Source

Dimino I.,The Italian Aerospace Research Center | Vitiello P.,The Italian Aerospace Research Center | Aliabadi F.M.H.,Imperial College London
Recent Patents on Mechanical Engineering

Sound radiation from vibrating panels plays a crucial role in the study of interior noise in transportation vehicles. In recent years, several patents have been issued for inventions in the field of sound reduction technologies to mitigate aircraft noise. This work presents a theoretical analysis and simulations to investigate sound transmission through plate-like multi wall structures. An analytical model is developed to predict sound transmission through infinite-sized triple panel partitions placed in a rigid baffle, from a viewpoint of practical noise control. A numerical procedure is also developed to evaluate the transmission characteristics of finite partitions due to an incident diffuse field. The method is based on a hybrid FEM/Rayleigh methodology and utilizes numerically calculated sound transmission loss of flat multi panel partitions and box like cavities with idealized boundary conditions. Two simplifying assumptions are made: the surrounding medium is air and the radiated sound power is calculated by an array of discrete elemental radiators. Several examples are presented to demonstrate the accuracy of the proposed approach. A theoretical performance analysis is finally carried out on a triple panel partition representative of a more complex triple wall aircraft-type window. The testbed design, used for this study, is guided by an effort to quantify sound insulation capabilities of aircraft windows with a specific focus on passenger's protection against noise transmitted through fuselage panels. © 2013 Bentham Science Publishers. Source

Sanders L.,ONERA | Mincu D.-C.,ONERA | Denis W.,ONERA | Vitagliano P.L.,The Italian Aerospace Research Center | And 4 more authors.
20th AIAA/CEAS Aeroacoustics Conference

This paper deals with the computation of CROR installation effects in terms of tone noise within three separated steps. The first step aims at computing the aeroacoustic sources of a CROR by a CFD approach, namely a URANS method applied to counter-rotative propellers. The second step computes the acoustic field radiated by the isolated CROR. It is based on the Ffowcs-Williams and Hawkings (FW-H) surface integral method and uses the blade pressure fluctuations computed by CFD as input data. The last step computes the acoustic field scattered by the aircraft geometry within the Boundary Element Method using the incident acoustic field previously computed. This approach in three steps is applied on a 1/7th scale model of a regional aircraft design equipped with two CRORs and tested in windtunnel. The paper first focuses on the aeroacoustic study of the CROR including the effects of pylon and incidence. The numerical prediction of the CROR noise in take-off conditions is then compared to the experimental measurements of the isolated engine. The isolated CROR noise computation is globally underestimated compared to the measurements because it doesn't take into account the acoustic reflections occuring in the windtunnel but a qualitative agreement is found between the computation and the measurements. Finally, the computation of CROR installation effects is presented in one of the aircraft configuration tested in windtunnel, showing a global increase of the tones when the CROR is installed in comparison with the isolated configuration. Source

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