Abstract
Reduction of atmospheric emissions is currently a mandatory requirement for aircraft manufacturers. Several studies performed on Blended Wing–Body configurations showed a promising capability of reducing fuel consumption by increasing, at the same time, passengers’ transport capabilities. Although several aerodynamic studies are available at transonic speeds, low-speed evaluations of aerodynamic performances of Blended Wing Body aircrafts are less investigated. In this framework, the present paper deals with the aerodynamic performance of the N2A aircraft prototype at low-Mach number conditions. Aircraft longitudinal aerodynamics is addressed at M∞=0.2 with steady state three-dimensional RANS simulations carried out at two Reynolds numbers equal to 6.60×106 and 1.27×108, respectively. The former refers to an experimental test campaign performed at NASA Langley 14-by-22 foot subsonic tunnel, while the latter is related to free-flight conditions close to an approach and landing phase. Flowfield simulations are performed using the Computational Fluid Dynamic code FLUENT and the SU2 open-source code, currently adopted for research applications. Numerical solutions are validated by using available experimental data with reference to lift, drag, pitching moment and drag polar estimations. Pre-stall and post-stall aerodynamic behaviour through mean flow-field visualization along with the comparison of pressure distributions at several AoAs is addressed. Furthermore, the effect of convective discretization on a numerical solution for SU2 is discussed. Results indicate a good agreement with available experimental predictions. The present study aims to bridge existing computations at a Eulerian low-Mach number, with RANS computations and constitutes a further test-case for SU2 code with respect to a full aircraft configuration.
Highlights
The mandatory urge to reduce atmospheric emissions caused by the recent climate changes has been reflecting on the design of commercial aviation aircrafts
Several conceptual studies performed by McDonnell Douglas, and the joint collaboration of NASA and Boeing, demonstrated that Blended Wing–Body (BWB) aircraft represent promising configurations to improve aerodynamic efficiency and to reduce fuel consumption compared to the conventional Tube and Wing (TAW) configurations [2,3]
The present study focuses on the aerodynamic analysis of a BWB prototype, namely N2A, at low-Mach number conditions with the aim to explore and assess the accuracy of flowfield simulations carried out with grids built with about 15 M cells, suitable for Multidisciplinary Design Optimization (MDO) procedures
Summary
The mandatory urge to reduce atmospheric emissions caused by the recent climate changes has been reflecting on the design of commercial aviation aircrafts. Because computing facilities made it possible to perform Euler or RANSbased simulations inside optimization loops, several toolkits developed for aerodynamic simulations become effective for BWB design [8] In this scenario, affordable and less time-consuming numerical codes with robust numerical schemes and accurate domain discretizations are of fundamental importance to have a reliable design tool to feed Multidisciplinary Design Optimization (MDO) procedures [6,9,10]. The data gathered make an interesting validation case due to the unconventional aeroshape and allows for bridging the existing CFD results, available in literature for transonic Mach numbers, with the low-subsonic ones It will shed light on the potential capability of SU2 work to be employed to build several computations for a complete aircraft configuration
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