bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energy approach to transonic flutter and LCO with shock waves movement
Authors: Kuzmina S , Ishmuratov F , Karas O 
Published: January 2021

Abstract
The paper briefly describes the main features of the used mathematical model of aerodynamic forces in transonic flow. The model is based on the Euler equations in various approximations, the boundary layer theory and viscous-inviscid interaction. Structural elastic deformations are described by equations in modal coordinates. The algorithm for computation of dynamic aeroelasticity characteristics in transonic flow has been developed on the base of energy method.
The problem of transonic self-oscillations and their relationship with the pressure distribution peculiarities and shock waves motion is numerically investigated using the CAST wing section as example. The dependence of aeroelastic stability characteristics on the distributed work of aerodynamic forces along the wing chord is shown. An approach to the creation of a numerical modeling methodology is developed for LCO processes in the time domain.
A CFD study on the strut interference on a regional aircraft wind-tunnel model
Authors: Russo S , Müller J , Alderman J , Paletta N , Adden S , Ruiz-Calavera L P 
Published: January 2021

Abstract
The aim of this paper is to investigate the aerodynamic interference effects of typical devices supporting aircraft models during wind tunnel tests by means of CFD tools. This work proposes the use of steady RANS simulations of the flow field in order to predict the interference produced by two different models of struts: (1) one that is made up of two parts and is solidal with the wind-tunnel model for variation of the angles of incidence (α) and of the angles of sideslip (β) and (b) the second that is made up of one part and is fixed for α variations and is solidal with the model for β variations. Low and high Reynolds flow conditions are considered and a typical cruise configuration of a scaled model of regional aircraft is addressed in both power-off and power-on conditions. The strut effect is investigated for several angles of incidence and sideslip. From the numerical point of view, the flow field and forces disturbance caused by the struts are derived by comparing simulations with and without the support. The interference is analysed in terms of global forces and moments coefficients and local quantities, such as pressure coefficients distributions. The main result regarding the comparison between the two models of strut is that the corrections to be applied to experimental data and the effect of both ventral struts on the global aerodynamic forces and moments are small.
Non-intrusive determination of the unsteady surface pressure and aerodynamic loads on a pitching airfoil
Authors: Mertens C , Sciacchitano A , van Oudheusden B W , Sodja J 
Published: January 2021

Abstract
The unsteady surface pressure distribution and aerodynamic loads on a pitching airfoil are determined non-intrusively using PIV measurements. An experimental test case is considered where the flow around the airfoil is mostly attached while the unsteady effects on the aerodynamic loads are significant. The surface pressure is calculated from the flow velocity measurements in the vicinity of the airfoil surface, that are obtained with a robotic PIV system, by using relations from unsteady potential flow and thin airfoil theory. The proposed approach is a robust and computationally efficient approach to obtain non-intrusive measurements of the unsteady surface pressure distribution and the aerodynamic loads, that are in good agreement with reference data from installed pressure transducer sensors.
Measurements of deformation, schlieren and forces on an OAT15A airfoil at pre-buffet and buffet conditions
Authors: Accorinti Alessandro , Baur Tim , Scharnowski Sven , Knebusch Johannes , Dillinger Johannes , Govers Yves , Nitzsche Jens , Kahler Christian J. 
Published: January 2021

Abstract
Self-sustained shock wave oscillations on airfoils, commonly defined as shock buffet, can occur under certain combinations of transonic Mach number and angle of attack due to the interaction between the shock and the separated boundary layer. To help understanding buffet physics, a rigid supercritical wing model (OAT15A) was investigated in pre-buffet and buffet conditions using a combined application of BOS (Background Oriented Schlieren), deformation and force measurements. From the observation via BOS of the change of the shock location and the extent of the boundary layer separation with the AoA (angle of attack), the transition from stable shock to buffet was detected. A comparison with other research groups at supposedly similar aerodynamic conditions highlighted a great disparity among them in terms of buffet onset, amplitudes of buffet oscillations, and flow development (motion of the mean shock location with the AoA) after the onset. The average and rms (root mean square) of the surface displacement were computed together with the effective geometric AoA, taking into account the static torsional deformation of the model and its support. Moreover, the spectra of the balance and deformation data showed the same buffet peak as in the BOS spectrum, indicating a coupling between structure and flow, which increased with the AoA.
Design of a tilting mechanism for a VTOL flying wing UAV
Authors: Mitridis D , Bliamis C , Kaparos P , Yakinthos K 
Published: January 2021

Abstract
In this paper, the detailed design of a mechanism for the transition from vertical to horizontal flight of a Vertical Take-off and Landing (VTOL) fixed wing Unmanned Aerial Vehicle (UAV) is presented. The UAV, which is being developed in the framework of the MPU research project, under the designation MPU RX-4, is a lightweight, all electric driven UAV with a flying wing layout. The MPU RX-4 is capable of performing both conventional flight, like a regular fixed wing aerial vehicle, as well as vertical hovering, like a multicopter, adapting on different operational demands. To achieve that, the development of a robust transition procedure from one flight phase to the other is required. This procedure is based on mechanisms capable of altering the flying characteristics of the UAV. More specifically, these mechanisms should be designed in order to change the orientation of the thrust vectors from horizontal to vertical and vice versa. MPU RX-4 uses a configuration of three electric motors (two mounted on the canards, and one in the main body) in order to perform both flight phases. For the transition from the hovering phase to the level flight, the two frontal motors have to be tilted from the vertical position to the horizontal, and the rear motor to be nested in its proprietary position, using four external hatches. Two separate mechanisms are designed, one for the canards’ tilting movement and another one for the extension and retraction of the rear motor hatches. Finite Element Analysis is carried out for the structural sizing of the mechanism (i.e. internal loads, linkages cross-section, joints sizing). The aerodynamic loads, acting on the mechanisms, are derived from Computational Fluid Dynamics analysis performed for the various flight phases (hovering, level flight and transition) of the UAV. Finally, the designed mechanisms are presented as integrated parts of the prototype UAV.
Enhancing preliminary aircraft design through operational considerations: a data-driven approach
Authors: Longueville Sébastien de , Jézégou Joel , Bénard Emmanuel , Gourinat Yves 
Published: January 2021

Abstract
Nowadays, digitalisation of aircraft, of their operations and their support became a crucial component for all the market players of the aeronautical industry. This technical field occupies an increasingly significant place, due to the generation of a substantial volume and an extensive variety of operational data. This new trend suggests taking those data into account during preliminary design and certification steps, in order to include additional considerations during those phases, such as operational criteria, maintenance, added value, development times or certification delays. In that way, this paper aims at suggesting a methodology to consolidate the aircraft design and certification processes though the use of those novel “digital” resources.
Multi-disciplinary framework for propeller blade design
Authors: Kümmel A. , Breitsamter C. 
Published: January 2021

Abstract
Improved propeller designs are necessary to ensure an eco-friendly and resource-saving operation. The shape optimization of propellers involves different disciplines, which include the aerodynamics and the structural characteristics of the propeller. The requirements of the individual disciplines for the propeller design are contradictory and compromises must be made. To deal with this complex optimization task, a modular multi-disciplinary optimization framework is developed. The framework is based on a Python control script, which invokes the individual analysis modules. Within the framework, a blade element momentum theory approach for the aerodynamic analysis and a finite element method for the structural analysis are used. This allows for an efficient calculation of various designs. In a first step, a pure aerodynamic optimization is conducted. In a second step, structural constraints in form of the permissible material stress and the propeller blade tip deflection are considered. The results are compared to a design method, which calculates the blade shape for minimal induced losses.
From FAST to FAST-OAD: An open source framework for rapid Overall Aircraft Design
Authors: David Christophe , Delbecq Scott , Defoort Sebastien , Schmollgruber Peter , Benard Emmanuel , Pommier-Budinger Valerie 
Published: January 2021

Abstract
To face the increasing environmental footprint of commercial aviation, industrial and research efforts have been focusing on exploring unconventional configurations and new propulsion paradigms, mostly based on electric technology. Such explorations require Overall Aircraft Design that has to be performed in an integrated multidisciplinary design environment. Such design environments are often limited to multidisciplinary analysis, adapted for a single aircraft configuration or require an important effort to be mastered. FAST-OAD is a software program developed by ONERA and ISAE-SUPAERO for aircraft sizing analysis and optimization that aims at user friendliness and modularity. It is an aircraft sizing code based on multidisciplinary design optimization techniques and the point mass approach to estimate the required fuel and energy consumption for a given set of TLARs. This paper presents the motivations for moving from the original software program, called FAST, to the open source code FAST-OAD based on OpenMDAO.
Performance and emissions of a microturbine and turbofan powered by alternative fuels
Authors: Przysowa Radoslaw , Gawron Bartosz , Bialecki Tomasz , Lçgowik Anna , Merkisz Jerzy , Jasiński Remigiusz 
Published: January 2021

Abstract
BACKGROUND: Alternative fuels containing biocomponents produced in various technologies are introduced in aviation to reduce its carbon footprint but there is little data describing their impact on the performance and emissions of engines. OBJECTIVES: The purpose of the work is to compare the performance and gas emissions produced from two different jet engines: the GTM-140 microturbine and the full-size DGEN380 turbofan, powered by blends of Jet A-1 and one of two biocomponents: 1) ATJ and 2) HEFA produced from used cooking oil (UCO) in various concentrations. The acquired data will be used to develop an engine emissivity model to predict gas emissions. METHODS: Blends of the mineral fuel with synthetic components were prepared in various concentrations, and their physicochemical parameters were examined in the laboratory. Measurements of emissions from both engines were carried out in selected operating points using the Semtech DS gaseous analyzer and the EEPS spectrometer. RESULTS: The impact of tested blends on engine operating parameters is limited, and their use does not carry the risk of a significant decrease in aircraft performance or increase in fuel consumption. Increasing the content of biocomponents causes a noticeable increase in the emission of CO and some other gasses (HC and NOx), which should not, however, worsen the working conditions of the ground personnel. This implies that there are no contraindications against using tested blends for fuelling gas-turbine engines.
Development of a Flight Mechanics Simulation Computer based on a Flexible Aircraft Model for a Regional Aircraft
Authors: Malisani Simone , Capello Elisa , Guglieri Giorgio 
Published: January 2021

Abstract
The changes on aircraft structures and the increased use of advanced and light materials have led to the design of more efficient and flexible aircraft. This implies that rigid body dynamics is no longer sufficient to describe the aircraft behaviour in atmospheric flight. Coupling between structural and rigid body dynamics should be included, due to frequencies of structural modes. In this work, an analytical method, based on a mixed Newtonian-Lagrangian approach, is used to derive a simplified model of a flexible aircraft. Moreover, flexible displacements and torsional variables, starting from the Lagrange’s equations, are discretized by means of a finite number of generalized coordinates. This approach allows to derive directly a finite-order system of ordinary differential equations, making it less complex and suitable for real time simulation and control law synthesis. The main objective of the proposed methodology is the real-time implementation on a “flyable” hardware, for experimental tests, including sensor models. In detail, accelerometers on selected wing sections are design to measure the effect of flexibility in terms of bending and torsional deformations. A simplified low-order model is designed for a regional aircraft, including different masses and flight conditions. Moreover, only two symmetrical bending modes and one torsional mode are considered in the flexibility definition. Finally, the hinge moments acting on the control surfaces are evaluated. The hinge moment is calculated as the aerodynamic torque generated on the hinge axis by the variation of the pressure distribution acting on the control surfaces. A gust response of this aircraft is mainly analysed, considering both a discrete gust model and a continuous model. This research is performed within the ASTIB project, which has received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation program under grant agreement CSJU – GAM REG 2014-2015.
Foundations towards the future: FutPrInt50 TLARs an open approach
Authors: Eisenhut D , Windels E , Reis R , Bergmann D , Ilário C , Palazzo F , Strohmayer A 
Published: January 2021

Abstract
A hybrid-electric regional aircraft for 50 passengers has challenges in technology, operation and future regulations similar to larger class aircraft. It is thus at the right spot to drive technology, regulations and operational developments in order to accelerate cleaner flight technologies based on propulsion electrification. The FutPrInt50 team set up Top-Level Aircraft Requirements that aim to be a reference foundation for the development of specific topics handled in this H2020 project but also drive the open collaboration model adopted by FutPrInt50. In this paper the development of the mission statement will be explained for a hybrid-electric 50 passenger regional aircraft, which builds the framework for the Top-Level Aircraft Requirements. To further support development from these requirements, a mission scenario will be presented for this class of aircraft.
Determination of the 1st Buckling and Collapse Loads for Integrally Stiffened Panels by Artificial Neural Network and Design of Experiment Methodology
Authors: Guzel S , Gurses E 
Published: January 2021

Abstract
Buckling is a structural instability that load carrying capacity of a structural element may suddenly decrease. This sudden change in the load carrying capacity may cause catastrophic failures. Therefore, determination of the first buckling and collapse loads of structural elements is essential. FE analyses and structural testing are used to determine buckling characteristics of a structural element. However, in early design stages, FE analyses are time consuming and structural testing is costly. In this paper, artificial neural network tool is used to reduce computational effort to determine buckling loads of integrally stiffened structural panels in early design stages. Moreover, Latin Hypercube Sampling (LHS) methodology is used to reduce the number of required FE analyses to generate database that artificial neural network is based on. Mean errors and fit performance model results are compared to determine accuracy of the neural network results.
Development of a prototype test system for certification of curved fuselage panels
Authors: Jiménez M. , Cabrera R. , Armario J.L. , Graciani E. , Estefani A. , Muñoz K. , García E. , París F. 
Published: January 2021

Abstract
A prototype test system with capacity to reproduce combined loads representative of real loading cases of a curved fuselage panel has been developed. This prototype test system allows the structural validation of curved fuselage panels to be accomplished. The developed system is able to apply combined mechanical and pressurization loading states under quasi-static and dynamic loading conditions. It has been designed using CAD models and calculated with the aid of Finite Element models to ensure its integrity. A data acquisition system synchronized with a control system enables real time monitoring of test parameters.
Advanced Weather Awareness System for Small Air Transport vehicles: design advancements in the COAST project
Authors: Montesarchio M , Zollo A L , Ferrucci M , Bucchignani E 
Published: January 2021

Abstract
It is well known that, in the aviation sector, flights are strongly influenced by weather conditions, especially considering small aircrafts. This kind of vehicles, ideal for transportation on regional base, are having an increasing importance in the last decades. In the framework of the COAST (Cost Optimized Avionics SysTem) project, funded by Clean Sky 2, several key technologies are under development for the affordable cockpit and avionics in the area of small aircrafts. One of these technologies is AWAS (Advanced Weather Awareness System), devoted to increase the weather awareness of the pilots, providing on board information concerning monitoring and forecasting of weather hazards having not negligible potential impact on the aircrafts. AWAS technology is composed by two applications, namely AWAS on-ground and AWAS on-board, connected each other via a satellite link. The AWAS on-ground is the core of the entire system, devoted to provide on-board synthetic information concerning the weather hazards detected or forecast over an area defined according to the aircraft position. The weather information is extracted from the geodatabase of MATISSE (Meteorological AviaTIon Supporting SystEm), a prototype software developed by the Meteorology Laboratory of CIRA, in which weather data coming from different sources are stored. The AWAS on-board application, instead, is devoted to provide on-ground the required input information (such as the aircraft position). Moreover, it decodes the data received by the on-ground application and allows the visualization of weather information in the cockpit by means of a Human Machine Interface specifically designed for the project. In this work, the main features of the AWAS system are presented, along with the future activities to be carried out in the COAST project.
Compact Computing Platform for Future General Aviation in the COAST Project
Authors: Zaykov Pavel , Beran Jan , Axman Petr 
Published: January 2021

Abstract
The CS-23 category in the General Aviation domain requires affordable, greener technologies and support single-pilot operation. The CS2 COAST project addresses these needs by proposing i) a leap-change in computation performance, ii) reduction of development and operational costs, and iii) reduction of Size, Weight, Power, and Cost (SWaPC). In the COAST project, the findings in these technological areas are packaged in a common platform referred as a Compact Computing Platform (CCP). The CCP effort is split in two areas of development-Platform Engineering and Innovative Elements. The first area covers the development of the necessary Hardware (HW) and Software (SW) building blocks. The second area corresponds to the advanced features that provide product differentiation and competitive advantage on the market. In this paper, we briefly describe the most significant SW and HW components from both technological areas and their potential integration in a demonstrator.
Flight management enabling technologies for single pilot operations in Small Air Transport vehicles in the COAST project
Authors: Di Vito V , Beran J , Kabrt T , Grzybowski P , Rogalski T , Maslowski P , Montesarchio M 
Published: January 2021

Abstract
Small Air Transport (SAT) is emerging as suitable transportation means in order to allow efficient travel over a regional range, in particular for commuters, based on the use of small airports and fixed wing aircraft with 5 to 19 seats, belonging to the EASA CS-23 category. The affordability of the SAT industry needs to be supported by the availability of new technological solutions allowing reducing the related operational costs while at the same time maintaining the required flight safety levels. In this framework, Clean Sky 2 Joint Undertaking funded the project COAST (Cost Optimized Avionics SysTem), which started in 2016 with the aim of tackling this challenge and delivering key technology enablers for the affordable cockpit and avionics, while also enabling the single pilot operations for small aircraft. The project activities cover several technologies and, among them, some selected ones, specifically addressing flight management, are considered in this paper, whose aim is the one of providing an outline of the design and implementation process status reached up to date, emphasizing the obtained results and the work to be done in the future activities expected to be performed in the project. The selected technologies here considered are the ones of tactical traffic separation and enhanced situational awareness, meteorological enhanced awareness, and pilot’s incapacitation emergency management. The paper, therefore, focuses on a selected cluster, from the overall framework of the COAST project, of SAT single pilot operations enabling technologies: Tactical Separation System (TSS), Flight Reconfiguration System (FRS), and Advanced Weather Awareness System (AWAS). In the paper, a description is first reported of the overall COAST project objectives, motivations and approach to the SAT vehicles cockpit design. Then, the implemented design process is outlined and the description of each of the above-indicated selected technologies is presented (the additional technologies considered in the COAST project are out of the scope of this paper). Based on that, for each of the considered systems (TSS, FRS, AWAS) the status of the design and implementation process is described and the next steps expected to be implemented in the project are outlined.