Aerodynamic considerations of blended wing body aircraft

In this paper three ‘Images’ of air travel on a sustainable path in 2050 are outlined. The method used is backcasting. A stabilization of the carbon dioxide concentration in the atmosphere at 450 parts per million is assumed to constitute a sustainable level. It is concluded that a refinement of the conventional turbofan aircraft is probably not sufficient to reach even the less demanding target level, even though a 40% reduction of fuel intensity may be achieved. The introduction of more radical aircraft configurations, e.g. the flying wing, probably has the greatest potential for reducing fuel consumption, but the development of such aircraft is uncertain. A less risky strategy is to opt for a high-speed propeller aircraft with a cruise speed which is 20–25% lower than for a conventional turbofan aircraft. This configuration entails a 56% cut of carbon dioxide emissions per passenger-kilometre compared to 2000. If this technology trajectory is combined with a development characterized by a weakened emphasis on economic growth together with less hectic lifestyles, it may be possible to reach even the most demanding of the target levels. Air travel per capita in 2050 would then be slightly higher than in 2000. If only the less demanding target level is to be reached global air travel per capita may be about 110% higher than in 2000.

Sustainable air transport--on track in 2050

A study is presented of the effects of spanwise lift distribution on aerodynamic efficiency for a blended wing body (BWB) configuration of a given baseline planform. The baseline geometry is initially assessed by a high-fidelity aerodynamic model based on a multiblock structured grid Reynolds-averaged Navier-Stokes (RANS) solution. The accuracy of the simulation is investigated by a grid sensitivity study regarding total drag and its pressure drag and skin-friction drag components. Excessive outer wing loading with associated shock wave, hence, wave drag, has been revealed to be the major factor degrading the aerodynamic performance of the baseline BWB model. To relieve the outer wing, an efficient low-fidelity panel method aerodynamic model is used for the inverse design to achieve the target lift distributions through the variation of twist distribution along the span, shifting the load inboard. For the given BWB geometry, the baseline model is retwisted to achieve an elliptic, a triangular, and an averaged elliptic/triangular spanwise loading distribution. The designs are then analyzed using the high-fidelity RANS aerodynamic model. The wave drag component of the total drag for different span loadings is extracted from the flowfield solution to gain insight into the drag reduction provided by the new twist designs

Spanwise Lift Distribution for Blended Wing Body Aircraft.

This paper presents aerodynamic studies of a blended wing body (BWB) configuration within an European project, MOB. Firstly, the effects of spanwise distribution on the BWB aircraft aerodynamic efficiency were studied through an inverse design approach, combining both a low fidelity panel method and a high fidelity RANS method. Secondly, the BWB aerofoil profiles were optimised for improved performance. Finally, three-dimensional optimisation of the BWB twist and camber distribution were carried out based on continuous and discrete adjoint approaches.

http://aircraftdesign.nuaa.edu.cn/MDO/ref/Disciplinary%20Optimization/Aerodynamic%20optimization/AIAA-2002-5448.pdf

Aerodynamic studies for blended wing body aircraft

Aeronautics and astronautics are two closely related disciplines, sometimes found under the joint term aerospace, that have progressed at a formidable pace during the 20th century. Their im...

A.I Dunaevsky

Papers

Flying wing—problems and decisions