Fabrizio Nicolosi

Bio: Fabrizio Nicolosi is an academic researcher from University of Naples Federico II. The author has contributed to research in topics: Aerodynamics & Wind tunnel. The author has an hindex of 17, co-authored 77 publications receiving 782 citations. Previous affiliations of Fabrizio Nicolosi include Aeronáutica.

Aerodynamic guidelines in the design and optimization of new regional turboprop aircraft

Abstract: This paper aims to provide some guidelines in the aerodynamic design and optimization of future regional turboprop aircraft with about 90 passengers. Currently there are no configurations on the market of this type, thus a typical 70 passengers turboprop aircraft is taken as reference starting point. The most critical aircraft components in terms of aerodynamic drag contribution and possible improvement are highlighted and an automatic procedure manageable trough MATLab ® is described. This interfacing procedure allows importing and modifying geometries using interpolating curves and surfaces via NURBS. Within the optimization loop, any new geometry is analyzed trough the panel code solver until optimized shapes are found. Wing–fuselage junction (also called “Karman”), undercarriage pod, fuselage nose and wing-tip device have been investigated and estimation of performance advantages has been computed. Design of the winglet is presented highlighting performance improvements during the entire mission profile. Finally two different turboprop configurations are proposed: the first with a 4-abreast fuselage arrangement and the second with 5-abreast, highlighting pros and cons of each configuration.

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

Abstract: 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.

Design and aerodynamic analysis of a twin-engine commuter aircraft

Abstract: The present paper deals with the preliminary design of a new general aviation Commuter 11 seat aircraft. The commuter aircraft market is today characterized by very few new models and the majority of aircraft in operation belonging to this category are older than 35 years. Tecnam Aircraft Industries and the Department of Industrial Engineering (DII) of the University of Naples “Federico II” have been deeply involved in the design of a new commuter aircraft that should be introduced in the market with very good opportunities of success. This paper aims to provide some guidelines on the conceptual design of this new twin-engine commuter aircraft. Aircraft configuration and cabin layout choices are shown and compared to similar solutions adopted by main competitors. The aerodynamic analyses are focused on some particular effects such as the wing–fuselage interference and the nacelle lift contribution and their effect on wing span loading. The aerodynamic analyses have been also essential to validate the preliminary estimation of aircraft stability and control derivatives (both longitudinal and lateral–directional) and to lead to a right sizing of tail surfaces. These analyses have been carried out through the use of a 3-D panel code. Finally some preliminary wind tunnel test results are presented.

An investigation on vertical tailplane contribution to aircraft sideforce

Abstract: The paper presents a deep investigation on the aerodynamics of the vertical tailplane and the correct estimation of its contribution to aircraft directional stability and control, especially during the preliminary design phase. Nowadays the most used methodologies in preliminary design to estimate the contribution of vertical tailplane on aircraft directional stability and control are (i) the classical method proposed by USAF DATCOM (also presented in several aeronautics textbooks) and (ii) the method presented in ESDU reports. Both methodologies derive from NACA World War II reports of the first half of the ʼ900, based on obsolete geometries that do not represent the typical shape of a transport aircraft. The other limit is that these methods give quite different results for certain configurations, e.g. in the case of horizontal stabilizer mounted in fuselage. As shown in literature, the main effects on the sideforce coefficient of the vertical tail are due to the interactions among the aircraft components. In order to better highlight these effects, a different approach using the RANS equations has been adopted. Several CFD calculations have been performed on some test cases (used as experimental database) described in NACA reports to verify the compliance of CFD results with available experimental data. The CFD calculations (performed through the use of a parallel supercomputing platform) have shown a good agreement between numerical and experimental data. Subsequently the above mentioned effects have been deeply investigated on a new set of aircraft configurations. The configurations that have been prepared differ among them for wing aspect ratio, wing–fuselage relative position (high-wing/low-wing), vertical tailplane aspect ratio (vertical tail span versus fuselage height) and horizontal tailplane position respect to the vertical tailplane (with the aim of investigating the effect of fin-mounted T configuration, typical of regional turboprop transport aircraft). All the CFD analyses have been carefully post-processed and have been useful to obtain new curves to predict the above mentioned effects and thus to have a more accurate estimation of vertical tailplane contribution to aircraft directional stability and control.

Aircraft directional stability and vertical tail design: A review of semi-empirical methods

Abstract: Aircraft directional stability and control are related to vertical tail design. The safety, performance, and flight qualities of an aircraft also depend on a correct empennage sizing. Specifically, the vertical tail is responsible for the aircraft yaw stability and control. If these characteristics are not well balanced, the entire aircraft design may fail. Stability and control are often evaluated, especially in the preliminary design phase, with semi-empirical methods, which are based on the results of experimental investigations performed in the past decades, and occasionally are merged with data provided by theoretical assumptions. This paper reviews the standard semi-empirical methods usually applied in the estimation of airplane directional stability derivatives in preliminary design, highlighting the advantages and drawbacks of these approaches that were developed from wind tunnel tests performed mainly on fighter airplane configurations of the first decades of the past century, and discussing their applicability on current transport aircraft configurations. Recent investigations made by the authors have shown the limit of these methods, proving the existence of aerodynamic interference effects in sideslip conditions which are not adequately considered in classical formulations. The article continues with a concise review of the numerical methods for aerodynamics and their applicability in aircraft design, highlighting how Reynolds-Averaged Navier-Stokes (RANS) solvers are well-suited to attain reliable results in attached flow conditions, with reasonable computational times. From the results of RANS simulations on a modular model of a representative regional turboprop airplane layout, the authors have developed a modern method to evaluate the vertical tail and fuselage contributions to aircraft directional stability. The investigation on the modular model has permitted an effective analysis of the aerodynamic interference effects by moving, changing, and expanding the available airplane components. Wind tunnel tests over a wide range of airplane configurations have been used to validate the numerical approach. The comparison between the proposed method and the standard semi-empirical methods available in literature proves the reliability of the innovative approach, according to the available experimental data collected in the wind tunnel test campaign.

Wind turbine design with emphasis on Darrieus concept Ion Paraschivoiu

Abstract: Wind energy is the fastest growing alternate source of energy in the world since its purely economic potential is complemented by its great positive environmental impact. The wind turbine, whether it may be a Horizontal-Axis Wind Turbine (HAWT) or a Vertical-Axis Wind Turbine (VAWT), offers a practical way to convert the wind energy into electrical or mechanical energy. Although this book focuses on the aerodynamic design and performance of VAWTs based on the Darrieus concept, it also discusses the comparison between HAWTs and VAWTs, future trends in design and the inherent socio-economic and environmental friendly aspects of wind energy as an alternate source of energy.

State-of-the-art in aerodynamic shape optimisation methods

Abstract: Aerodynamic optimisation has become an indispensable component for any aerodynamic design over the past 60 years, with applications to aircraft, cars, trains, bridges, wind turbines, internal pipe flows, and cavities, among others, and is thus relevant in many facets of technology. With advancements in computational power, automated design optimisation procedures have become more competent, however, there is an ambiguity and bias throughout the literature with regards to relative performance of optimisation architectures and employed algorithms. This paper provides a well-balanced critical review of the dominant optimisation approaches that have been integrated with aerodynamic theory for the purpose of shape optimisation. A total of 229 papers, published in more than 120 journals and conference proceedings, have been classified into 6 different optimisation algorithm approaches. The material cited includes some of the most well-established authors and publications in the field of aerodynamic optimisation. This paper aims to eliminate bias toward certain algorithms by analysing the limitations, drawbacks, and the benefits of the most utilised optimisation approaches. This review provides comprehensive but straightforward insight for non-specialists and reference detailing the current state for specialist practitioners.

Three-dimensional effects and arm effects on modeling a vertical axis tidal current turbine

Abstract: Three-dimensional effects in studying a vertical axis tidal current turbine are modeled using a newly developed vortex method The effects on predicting power output and wake trajectory are analyzed in particular The numerical results suggest that three-dimensional effects are not significant when the height of the turbine is more than seven times the turbine radius Further discussions are presented focusing on the relationship between the turbine height and the angle of attack and the induced velocity on a blade of the turbine without arms Besides the three-dimensional effects, arms effects are quantified with an analytical derivation of the polynomial formula of the relationship between arm effects and the tip speed ratio of the turbine Such a formula provides a correction for existing numerical models to predict the power output of a turbine Moreover, a series towing tank tests are conducted to study the three-dimensional effects as well as the arm effects Good agreements are achieved between the results obtained with numerical calculations with the arm effects correction and the towing tank tests Finally, three-dimensional effects are examined experimentally together with the arm effects by using an end-plate test, which suggests that the combinational effect is rather minimal For turbine designers at the early design stage, we recommend that a two-dimensional model is acceptable considering the high cost of the three-dimensional model