Italian Aerospace Research Centre

About: Italian Aerospace Research Centre is a other organization based out in Capua, Campania, Italy. It is known for research contribution in the topics: Aerodynamics & Morphing. The organization has 278 authors who have published 400 publications receiving 3563 citations. The organization is also known as: CIRA & Italian Aerospace Research Center.

Aerodynamic Analyses of Tiltrotor Morphing Blades

Abstract: Technology is progressing very quickly, and many things which, in the past, seemed to be mere fantasy are now at hand. Morphing structures, mimicking the natural adaption of bird wings in flight, are being developed for use on actual aircraft to replace traditional hinged lifting surfaces. Tiltrotors for civil aviation are not in service yet, but researchers are exploring integration of disruptive technologies in order to enhance their performance while simultaneously reducing their environmental impact related to noise and chemical emissions. Morphing blades may be too complex to be used together with tiltrotors for industrial applicability. Nevertheless, assessing the possible benefits of this arrangement allows researchers to stay current with technological advancements and allows them to introduce the most advanced products possible to the market. This path has inspired the work described hereafter. This text summarizes researchers efforts to develop advanced tiltrotor blades (via passive optimization) and morphing devices capable of in-flight radial and chordwise modification of blade shape. All of the tools utilized in these numerical simulations (disciplinary analysis codes, interfaces, automatic procedures, software integration environments) are outlined, and the expected benefits of their application to a realistic case study form the basis of later discussion.

Dynamic Pulse Buckling of Composite Stanchions in the Sub-Cargo Floor Area of a Civil Regional Aircraft.

Abstract: This work is focused on the investigation of the structural behavior of a composite floor beam, located in the cargo zone of a civil aircraft, subjected to cyclical low-frequency compressive loads with different amplitudes. In the first stage, the numerical models able to correctly simulate the investigated phenomenon have been defined. Different analyses have been performed, aimed to an exhaustive evaluation of the structural behavior of the test article. In particular, implicit and explicit analyses have been considered to preliminary assess the capabilities of the numerical model. Then, explicit non-linear analyses under time-dependent loads have been considered, to predict the behavior of the composite structure under cyclic loading conditions. According to the present investigation, low-frequency cyclic loads with peak values lower than the static buckling load value are not capable of triggering significant instability.

On the Experimental Characterization of Morphing Structures

Abstract: A major difficulty in the design of morphing devices for aircraft wings is to reach an adequate compromise between high load-carrying capacity to withstand aerodynamic loads and sufficient flexibility to achieve better aerodynamic performance. Such counteracting and demanding targets lead to an increased structural complexity whose experimental characterization is a matter of high priority prior to the ultimate physical integration into the aircraft structure. Compared to the passive counterpart, morphing devices enable augmented capabilities by locally adapting wing shape and lift distribution through either a quasistatic or dynamic deflection, with excursions ranging into a few units of degrees, positive and negative. This chapter provides an overview of the verification approaches suitable for morphing devices ranging from the basic concepts applicable to individual subsystems up to the global experimental analysis of the integrated system. A number of test objectives are illustrated at both component and system level, providing practical tips for the experimental analysis of morphing structures combining both compliant structural systems and multibox self-contained actuation mechanisms.

Application of Surrogate-Based Optimization Techniques to Aerodynamic Design Cases

Abstract: The paper proposes the application of evolutionary-based optimization coupled with physics-based and adaptively-trained surrogate model to the solution of both two- and three-dimensional aerodynamic optimization problems. The shape parameterization approach consists of the Class-Shape Transformation (CST) method with a sufficient degree of Bernstein polynomials to cover a wide range of shapes. The in-house ZEN flow solver is used for RANS aerodynamic solution. Results show that, thanks to the combined usage of surrogate models and smart training, optimal candidates may be located in the design space even with limited computational resources with respect to standard global optimization approaches.

Evolution of flow structures in twin-rotors wakes in drones by time-resolved PIV

Abstract: An experimental investigation of the noise emissions of a twin-rotor together with the evolution and spatial organization of the flow structures wakes has been carried out by means of aeroacoustics and time-resolved PIV (TR-PIV) measurements. Each rotor is characterized by three bladed propellers with diameter D = 393.7 mm running at four different rotational speeds (2620, 3500, 4360, 5200 RPM). Intricate flow patterns characterized by periodic vortical structures are formed in the wake of the rotors in twin configuration at the rotor-to-rotor distance of 1.02D. Their interaction determines a strong impact on the aerodynamic performances as well as on the noise generation. Hence, the need for TR-PIV measurements relies on what is the role of these instantaneous flow patterns to unveil the spatial organization and the dynamic behaviour inspected by imaging the region between the rotors. It is found that the flow organization and the interaction between evolution of vorticity intensity of tip vortices characterize the twin-rotors wakes.