Analysis for a wing nacelle configuration

The paper presents CFD results for a wing-nacelle configuration, in order to be testedagainst an analytic solution considering nacelles as chord discontinuities

Using genetic algorithms to optimize airfoils in incompressible regime

Aerodynamic optimization is a very actual problem in aircraft design and airfoils are basic two-dimensional shape forming cross sections of wings. Traditionally, the airfoil geometry if defined by a very large number of coordinates. Nowadays, in order to simplify the optimization, the airfoil geometry is approximated by a parametrization, which enables to reduce the number of needed parameters to as few as possible, while effectively controlling the major aerodynamic features. The present work has been done on the Class-Shape function Transformation method (CST) [1, 2]. Also, the paper introduces the concept of Genetic Algorithm (GA) to optimize a NACA airfoil for specific conditions. A Matlab program has been developed to implement CS into the Global Optimization Toolkit. The pressure distribution lift and drag coefficients of the airfoil geometries have been calculated using two programs. The first one is an in-house code based on the Hess-Smith [3] panel technique and on the boundary layer integral equations, while the second is an XFOIL program. The optimized airfoil has improved aerodynamic characteristics as compared to the original one. The optimized airfoil is validated using the Ansys-Fluent commercial code

Estimation of Wind Tunnel Corrections Using Potential Models

The evaluation of the tunnel correction remains an actual problem, especially for the effect of tunnel walls. Even if the experimental campaign meets the basic similitude criteria (Mach, Reynolds etc.), the wall effect on the measured data is always present. Consequently, the flow correction due the limited by walls must be evaluated. Solid wall corrections refer to the aerodynamic interference between the experimental model and the walls of the wind tunnel. This interaction affects the measured forces and implicitly the angle of attack. Usually, these effects are introduced through semi-empirical correction factors which change the global measured forces. The present paper refers to the mathematical and numerical modeling of aerodynamic interferences between the experimental model and the solid walls based on the potential flow model. The main goal is to asses a method allowing an estimate of the corrections for each configuration with a minimum computational resource

Coherent solutions to roll damping derivatives evaluation for a generic rocket model

This paper presents a coherent approach to evaluate the roll damping derivatives for the standard Basic Finner Model. The study compares and analyses the results obtained through a range of techniques, including experimental testing, numerical simulations and semi-empirical models. The study aims to evaluate the reliability and accuracy of these methods and to identify the factors that contribute to their sensitivity. The paper concludes by summarizing the findings of the study and discussing the implications of the results for the design and operation of rockets. The experimental and numerical analysis used in this study provides a robust and comprehensive evaluation of the roll damping coefficient

Drag coefficient modelling in the context of small launcher optimisation

The purpose of this paper is to present a fast mathematical model that can be used to quickly asses the drag coefficient for generic launcher configurations. The tool developed based on this mathematical model can be used separately or it can be integrated in a multidisciplinary optimisation algorithm for a preliminary microlauncher design

MDO approach for a two-stage microlauncher

The paper focuses on the multidisciplinary optimisation and preliminary design of a two-stage microlauncher capable of inserting a small 50 kg payload into Low Earth Orbit. The microlauncher is obtained using a MDO approach, where the lightest configuration capable of reaching the target orbit is considered to be optimal. For this paper, the propulsion system of the microlauncher is based on a non-cryogenic bipropellant combination

Wind Tunnel Testing of Passive High-Lift Systems

This paper presents experimental results obtained with passive high lift systems using a combination of smart flap kinematics and vortex generators. A mid-scale 2.5D wind tunnel model based on DLR-F15 is tested in INCAS Subsonic Wind Tunnel, swept at 30 deg, incorporating the slat, 54 flap/VG/chord extension configurations and test matrix, developed by Dassault-Aviation. INCAS designed, manufactured and instrumented components to be added to the existing INCAS-F15 2D wind tunnel model. The test campaign was completed and results are presented

End-to-end process of hollow spacecraft structures with high frequency and low mass obtained with in-house structural optimization tool and additive manufacturing

In the space sector the most decisive elements are: mass reduction, cost saving and minimum lead time; here, structural optimization and additive layer manufacturing (ALM) fit best. The design must be driven by stiffness, because an important requirement for spacecraft (S/C) structures is to reduce the dynamic coupling between the S/C and the launch vehicle. The objective is to create an end-to-end process, from the input given by the customer to the manufacturing of an aluminum part as light as possible but at the same time considerably stiffer while taking the full advantage of the design flexibility given by ALM. To design and optimize the parts, a specialized in-house tool was used, guaranteeing a load-sufficient material distribution. Using topological optimization, the iterations between the design and the stress departments were diminished, thus greatly reducing the lead time. In order to improve and lighten the obtained structure a design with internal cavities and hollow beams was considered. This implied developing of a procedure for powder evacuation through iterations with the manufacturer while optimizing the design for ALM. The resulted part can be then manufactured via ALM with no need of further design adjustments. To achieve a high-quality part with maximum efficiency, it is essential to have a loop between the design team and the manufacturer. Topological optimization and ALM work hand in hand if used properly. The team achieved a more efficient structure using topology optimization and ALM, than using conventional design and manufacturing methods

TOWARDS THE ELECTRIC PROPULSION

The paper presents benefits and drawbacks of the electric propulsion for the case of a ten seat commuter aircraft. An efficiency evaluation is made for an electric version of AEROTAXI, considered as a reference. The evaluation is projected to 2020, trying to meet the expected progresses in energy storage systems

Methods of flow visualization

Flow visualization is an important topic in scientific visualization and has been the subject of active research for many years. Typically, data originates from numerical simulations, such as those of computational fluid dynamics, and needs to be analyzed by means of visualization to gain an understanding of the flow. With the rapid increase of computational power for simulations, the demand for more advanced visualization methods has grown