Influence of Spanwise Load Distribution on Blended-Wing–Body Performance at Transonic Speed

Abstract

The influence of spanwise load distributions on the overall performance of a blended-wing–body (BWB) model at transonic speed is investigated to understand the tradeoffs between aerodynamic efficiency and wing structure weight. The overall performance improvement is measured by the net weight saving relative to the maximum takeoff weight (). A BWB model based on the reference shape of the Boeing second-generation BWB model is taken as the baseline model. Taking the elliptic and triangular spanwise loading as the two extreme distributions, models with varying spanwise loadings have been designed. High-fidelity Reynolds-averaged Navier–Stokes solutions coupled with an inverse design optimization code considering static aeroelasticity is used in the inverse design process. For the BWB models, shifting the spanwise load from the elliptic design toward the triangular design shows a significant reduction in wing root bending moment compared with the traditional civil transports, thus resulting in significant structural weight savings. A wing root bending moment relief of 19% is obtained for the averaged elliptic–triangular design relative to the elliptic design, whereas the loss in aerodynamic efficiency is only 4.4%. The combined effects result in a net weight saving between 0.63 and 1.86% of .