Fabrizio Nicolosi

Dynamic Behaviour of the Patented Kobold Tidal Current Turbine: Numerical and Experimental Aspects

This paper provides a summary of the work done at DPA on numerical and experimental investigations of a novel patented vertical axis and variable pitching blades hydro turbine designed to harness energy from marine tidal currents. Ponte di Archimede S.p.A. Company, located in Messina, Italy, owns the patented KOBOLD turbine that is moored in the Messina Strait, between the mainland and Sicily. The turbine has a rotor with a diameter of 6 meters, three vertical blades of 5 meters span with a 0.4 m chord ad hoc designed curved airfoil, producing high lift with no cavitation. The rated power is 160 kW with 3.5 m/s current speed, which means 25% global system efficiency. The VAWT and VAWT_DYN computer codes, based on Double Multiple Steamtube, have been developed to predict the steady and dynamic performances of a cycloturbine with fixed or self-acting variable pitch straight-blades. A theoretical analysis and a numerical prediction of the turbine performances as well as experimental test results on both a model and the real scale turbine will be presented and discussed.

Aerodynamic Interference Issues in Aircraft Directional Control

This work investigates the aerodynamic interference among airplane components caused by rudder deflection for a typical turboprop aircraft geometry through the computational fluid dynamics technique. At no sideslip, an airplane is in symmetric flight conditions. The rudder deflection creates a local sideslip angle close to the vertical tailplane, and this effect is increased by fuselage and horizontal tail. Typical semiempirical methods, such as United States Air Force Stability and Control Data Compendium (USAF DATCOM), do not take into account for these effects, proposing the same corrective parameters both for pure sideslip and rudder deflection conditions. Numerical analyses executed on several aircraft configurations with different wing and horizontal tailplane positions show that the interference factors are smaller than those predicted by the USAF DATCOM procedure, providing guidelines for a more accurate aircraft directional control analysis and hence rudder preliminary design.

Commuter aircraft aerodynamic characteristics through wind tunnel tests

Purpose This paper aims to deal with the experimental estimation of both longitudinal- and lateral-directional aerodynamic characteristics of a new twin-engine, 11-seat commuter aircraft. Design/methodology/approach Wind tunnel tests have been conducted on a 1:8.75 scaled model. A modular model (fuselage, wing, nacelle, winglet and tail planes) has been built to analyze both complete aircraft aerodynamic characteristics and mutual effects among components. The model has been also equipped with trailing edge flaps, elevator and rudder control surfaces. Findings Longitudinal tests have shown the goodness of the aircraft design in terms of aircraft stability, control and trim capabilities at typical clean, take-off and landing conditions. The effects of fuselage, nacelles and winglets on lift, pitching moment and drag coefficients have been investigated. Lateral-directional stability and control characteristics of the complete aircraft and several aircraft component combinations have been tested to estimate the aircraft components’ interactions. Research limitations/implications The experimental tests have been performed at a Reynolds number of about 0.6e6, whereas the free-flight Reynolds number range should be between 4.5e6 and 9.5e6. Thus, all the measured data suffer from the Reynolds number scaling effect. Practical implications The study provides useful aerodynamic database for P2012 Traveller commuter aircraft. Originality/value The paper deals with the experimental investigation of a new general aviation 11-seat commuter aircraft being brought to market by Tecnam Aircraft Industries and it brings some material on applied industrial design in the open literature.

Methodological enhancements in MDO process investigated in the AGILE European project

This paper presents methodological investigations performed in research activities in the field of MDO in overall aircraft design in the ongoing EU funded research project AGILE. AGILE is developing the next generation of aircraft Multidisciplinary Design and Optimization processes, which targets significant reductions in aircraft development costs and time to market, leading to cheaper and greener aircraft solutions. The paper introduces the AGILE project structure and describes the achievements of the 1st year (Design Campaign 1) leading to a reference distributed MDO system. A focus is then made on the different novel optimization techniques studied during the 2nd year, all willing to ease the optimization of complex workflows, characterized by high degree of discipline interdependencies, high number of design variables in the context of ∗Research Engineer, Information Processing and Systems Department, AIAA Member. †Post Doctoral Researcher, System Design and Performance evaluation Department ‡Research Engineer, Research and Innovation §Assistant Professor, Department of Industrial Engineering (DII), AIAA member ¶Professor, Department of Industrial Engineering (DII), AIAA member ‖Research engineer, Integrated Aircraft Design Department, AIAA member ∗∗Researcher, Propulsion Systems Aerodynamics Department

Collaborative Aircraft Design Methodology using ADAS linked to CEASIOM

The aircraft design stages, conceptual and preliminary, are necessarily collaborative bytheir very nature. An example design carried out in this paper brings the collaborativeaspects of design to l ...

A Numerical Study on a Vertical-Axis Wind Turbine with Inclined Arms

This work focuses on a particular type of vertical-axis wind turbine, in which a number of inclined arms with airfoil-shaped cross-sections are mounted to connect the principal blades to their hub. While the majority of the known studies on vertical-axis turbines is devoted to the role of principal blades, in most of the cases without taking into account other parts of the wind turbine, the objective of this work is to investigate the effect of uncommon arm geometries, such as the inclined arms. The inclined arms are known to have a potentially beneficial role in the power extraction from the wind current but, due to the complexity of the phenomena, the investigation on aerodynamics of this type of turbine is often impossible through analytical models, such as blade-element momentum theory. It turns out that adequate studies can only be carried out by wind tunnel experiments or CFD simulations. This work presents a methodical CFD study on how inclined arms can be used on a selected wind turbine configuration to harvest additional power from the wind. The turbine configuration, geometry, and some fundamental definitions are introduced first. Then an in-depth CFD analysis is presented and discussed.

Improving Aircraft Endurance Through Turbulent Separation Control by Pulsed Blowing

Boundary-layer unsteady blowing is one of the most advanced solutions for reducing aircraft parasite drags and flow separation at high angles of attack. It allows high lift along with low drag to be achieved and, because endurance is one of the most important performance parameters for certain types of aircraft, such as unmanned aerial vehicles, clearly the CL 3/2 /CD ratio has to be maximized. The main goal of the present investigation is to explore possible ways to obtain efficient turbulent boundary-layer control and, at the same time, to consider the practical problems connected to the installation of the device in a real wing. This study seeks mainly to verify the effectiveness of active control via pulsed blowing as a tool to delay boundary-layer separation. Numerical simulations and wind-tunnel experimental investigations on a wing model equipped with instruments are presented and the results discussed. An extensive numerical and experimental investigation on the parameters that can affect flow separation has been carried out. As a result of this analysis, it seems that tubing length produces the most significant effect on the resonant frequencies of a pulsed-blowing system, whereas slot exit and cavity volume mainly affect the resonant peak amplitude. The best actuation frequency varies, depending on the type of aerodynamic performance to be optimized (efficiency, lift, or endurance).

Development of a Java-Based Framework for Aircraft Preliminary Design and Optimization

T HEconceptual and preliminary design phases play a very important role for the development of the future transport aircraft. A computational framework capable of finding an optimal configuration satisfying several basic requirements would be an essential tool for industrial aircraft designers. Such software should be developed around all those basic principles and approaches to aircraft preliminary design well described in several textbooks on the subject [1–9]. Amodern preliminary aircraft design tool should be characterized by a certain level of accuracy and reliability (albeit using fast and simple semiempirical procedures), the capability to perform multidisciplinary analyses, and reasonably short computational times. Because of the particular relevance of production costs, noise, emissions,maintenance, andoperative costs in the commercial success of a transport aircraft, amodern software framework should be developedwith amultidisciplinary optimization (MDO) approach inmind.Another important aspect is the user-friendliness of the interface that should allow the user to interact with the design framework in an easy, fast, and efficient way. Of the same or even of more importance is the possibility to include in the software multiple fidelity analysis methods or to modify and develop new semi-empirical models to achieve better accuracy. It should also be possible to export the aircraft configuration geometry (e.g., as a CADmodel or a surface mesh) in one or more standard formats and to execute high-fidelity analyseswith external tools (e.g., computational fluid dynamics or Finite ElementMethod (FEM) solvers). Many aircraft design computational tools have been developed by several universities, companies, aeronautical industries, and research centers in the past and recent years [10–17]. In many recent papers [18–21], the importance of including a knowledge-based engineering approach in modern aircraft design tools is highlighted. The present note introduces the ongoing development of the Java Program Toolchain for Aircraft Design (JPAD), a Java-based desktop application for aircraft designers. The aim of JPAD, which eventually will be released as open-source software, is to provide a library and a set of companion tools based onmodern software technology as a support for typical preliminary design studies. The software has been conceived to be used in an industrial environment across conceptual and preliminary design phases. In these phases, a lot of different configurations have to be considered, and so the proposed software relies mostly on semi-empirical analysis methods and is capable to quickly provide results. A comprehensive study of the methods available in the literature has been first carried out to improve the accuracy of the results; each method has been tested against experimental data (produced in house or drawn from literature) so that statistical quantities (e.g., standard deviation) could be estimated either to find the best method currently available or to make a merger of different methods. The use of middleand high-fidelity methods (e.g., in aerodynamics, numerical lifting line, vortex lattice method, or computational fluid dynamics) is beneficial in preliminary studies, provided that their computational time is reasonably short. In this respect, the development of new semi-empirical methodologies or improved analysis approaches (especially for innovative aircraft configuration) is an important item that has been extensively reported in several recent works [21–26]. The aircraft design research group at the University of Naples has matured in the past two decades experience in design of light and turboprop transport aircraft [27,28]. Recent aircraft design activities carried out by the authors on a commuter 11-seat aircraft has been described and illustrated in some recent papers [29,30]. The matured know-how in aircraft aerodynamic designs has also found confirm through specific flight-testing research [31,32].

A comprehensive review of vertical tail design

Purpose This work aims to deal with a comprehensive review of design methods for aircraft directional stability and vertical tail sizing. The focus on aircraft directional stability is due to the significant discrepancies that classical semi-empirical methods, as USAF DATCOM and ESDU, provide for some configurations because they are based on NACA wind tunnel (WT) tests about models not representative of an actual transport airplane. Design/methodology/approach The authors performed viscous numerical simulations to calculate the aerodynamic interference among aircraft parts on hundreds configurations of a generic regional turboprop aircraft, providing useful results that have been collected in a new vertical tail preliminary design method, named VeDSC. Findings The reviewed methods have been applied on a regional turboprop aircraft. The VeDSC method shows the closest agreement with numerical results. A WT test campaign involving more than 180 configurations has validated the numerical approach. Practical implications The investigation has covered both the linear and the non-linear range of the aerodynamic coefficients, including the mutual aerodynamic interference between the fuselage and the vertical stabilizer. Also, a preliminary investigation about rudder effectiveness, related to aircraft directional control, is presented. Originality/value In the final part of the paper, critical issues in vertical tail design are reviewed, highlighting the significance of a good estimation of aircraft directional stability and control derivatives.

Game theory and evolutionary algorithms applied to MDO in the AGILE European project

In this paper, an optimization technique in aircraft design field, based on game theory and evolutionary algorithms to define the key variables for Multi-Disciplinary aircraft Optimization (MDO) into AGILE (Aircraft 3 Generation MDO for Innovative Collaboration of Heterogeneous Teams of Experts) European project, is presented. This work represents one of the contributions given by UniNa (University of Naples “Federico II”) research group within the AGILE project, which is coordinated by the DLR and funded by EU through the project HORIZON 2020 that aims to create an evolution of MDO, promoting a novel approach based on collaborative remote design and knowledge dissemination among various teams of experts. Since the aircraft design field is very complex in terms of number of involved variables and the dimension of the space of variation, it is not feasible to perform an optimization process on all the design parameters; this leads to the need to reduce the number of the parameters to the most significant ones. A multi-objective optimization approach allows many different variables, which could be a constraint or an objective function for the specific investigation; thus, setting the constraints and objectives to reach, it is possible to perform an optimization process and control which parameters significantly affect the final result. Within AGILE project, UniNa research group aims to perform wing optimization processes in a preliminary design stage, coupling Nash game theory (N) with typical genetic evolutionary algorithm (GA), reducing computational time and allowing a more realistic association among objective functions and variables, to identify the main ones that significantly affect final result and that consequently must be considered by the partners of the AGILE consortium to perform MDO in the final part of project, applying the proposed optimization technique to novel aircraft configuration.