Browsing by Author "Benini, Ernesto"
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Item Open Access Computational design optimization for S-ducts(MDPI, 2018-10-12) D’Ambros, Alessio; Kipouros, Timoleon; Zachos, Pavlos; Savill, Mark; Benini, ErnestoIn this work, we investigate the computational design of a typical S-Duct that is found in the literature. We model the design problem as a shape optimization study. The design parameters describe the 3D geometrical changes to the shape of the S-Duct and we assess the improvements to the aerodynamic behavior by considering two objective functions: the pressure losses and the swirl. The geometry management is controlled with the Free-Form Deformation (FFD) technique, the analysis of the flow is performed using steady-state computational fluid dynamics (CFD), and the exploration of the design space is achieved using the heuristic optimization algorithm Tabu Search (MOTS). The results reveal potential improvements by 14% with respect to the pressure losses and by 71% with respect to the swirl of the flow. These findings exceed by a large margin the optimality level that was achieved by other approaches in the literature. Further investigation of a range of optimum geometries is performed and reported with a detailed discussion.Item Open Access Design evaluation and performance assessment of rotorcraft technology by 2050(Netherlands Aerospace Centre (NLR), 2019-09-17) Stevens, Jos; Rademaker, Edward; Scullion, Calum; Vouros, Stavros; van Oosten, Nico; Misté, Gianluigi; Venturelli, Giovanni; Nalianda, Devaiah; Pachidis, Vassilios; Benini, ErnestoThe extended Clean Sky Joint Technology Initiative (JTI) within the EU Horizon 2020 Framework Programme [Ref. 1] proposes to introduce a number of concept aircraft and rotorcraft to replace reference technology counterparts at different time scales (2020/2035/2050). This Clean Sky 2 (CS2) promotes the importance of those concept configurations and their application in the future. An increasing global demand within and outside the European Union (EU) for an efficient air mobility and transportation system (i.e. more flexible, resilient, effective and affordable), and future projected growth for its application, will lead to the requirement for development of highly optimised transportation solutions.Item Open Access Performance, environmental, and mobility analysis of large capacity fast rotorcraft configurations for the European regional air traffic market(DGLR Deutsche Gesellschaft für Luft- und Raumfahrt - German Society for Aeronautics and Astronautics, 2023-09-07) Declerck, Laurent; Cruellas Bordes, Marc; Saias, Chana Anna; Nalianda, Devaiah; Schreiner, B. Deneys J.; Misté, Gianluigi A.; Dal Monte, Andrea; Benini, Ernesto; Junior, AlfFast, large rotorcraft are of interest in the future European air transport system due to their runway independent operation and potential mobility improvements for the passenger. Both a tiltrotor and a coaxial compound concept model were developed for a 70 passenger, 500 NM design mission that would compete with regional fixed-wing aircraft. These models were flown along virtual trajectories representing possible use-cases and assessed for environmental performance in comparison to an in-service baseline aircraft using comparable engine technology levels. Further, the travel time and mobility improvement available to the intermodal transport network through the inclusion of these concept rotorcraft was examined with promising results. Future work is suggested to address the shortfall in environmental performance.Item Open Access Robust design optimisation of S-ducts(AIAA, 2022-06-20) Scaramuzzi, Andrea; Benini, Ernesto; Kipouros, TimoleonOver the past years, robust optimisations have become very popular and necessary. The aim of this type of optimisation is to consider the sensitivity of the output results to small variations in the operating conditions and manufacturing tolerances. To study such sensitivities, an accurate and efficient method to quantify the uncertainties in physical processes is necessary. We present here the study and design of an S-duct, suitable for distributed propulsion configurations, and we address practical considerations of the application of robust optimisation to real-world design problems under multiple uncertainties. Two different non-intrusive Polynomial Chaos techniques have been chosen to quantify the input and output uncertainties, namely the non-intrusive point collocation and the non-intrusive spectral projection. These two techniques were implemented in two different robust optimisation problems (R1D and R2D) and their optima designs were analysed. To demonstrate the effectiveness of the robust optimisation problem formulation and analysis we compared the newly discovered optimum designs with previous non-robust optimum configurations. The results are discussed in detail and have shown a clear reduction in swirl values at the AIP, without affecting the pressure recovery of the diffuser when uncertainty properties were considered. In addition, robust codes have found S-duct shapes with swirl standard deviation values that are an order of magnitude smaller than the NON-Robust optimized designs and the baseline geometry.Item Open Access Shape optimization of a curved duct with Free Form Deformations(AIAA, 2017-06-09) Chiereghin, Nicola; Guglielmi, Luigi; Savill, Mark; Manca, Enrico; Rigobello, Aurora; Barison, Marco; Benini, ErnestoThe Free Form Deformation method was applied to a S-duct geometry to reduce total pressure losses and flow distortion. The deformation method was coupled with a multiobjective genetic algorithm to optimize the shape of a diffusing S-duct, which was previously investigated, both numerically and experimentally. During the optimization process, 200 deformed shapes were tested with steady-state CFD simulations and the performances were evaluated both in terms of total pressure losses and swirl angle at the outlet. It was obtained a Pareto front with a maximum total pressure losses reduction of 20% and a maximum swirl reduction of 10%. The two extreme points of the Pareto front were further investigated by transient Detached Eddy Simulations to assess also the impact of the optimization on the flow instability. Surprisingly, one of the solutions showed stable and stationary vortical structures. This is in strong contrast with the previous investigations of the flow field time history of the baseline configuration, which outlined strong oscillations of the flow field combined with a high increase of the distortion parameters in comparison with the time-averaged flow field.