Aerodynamic-Structural Design Studies of Low-Sweep Transonic Wings

摘要

The current generation of wing designs for civilian air transport typically have a swept wing. However, these wings were designed without the aid of modern high-fidelity simulation and multidisciplinary optimization tools. With rapid advances in numerical simulation of high-Reynolds-number flows and efficient shape-optimization techniques, it is now possible to revisit the designs of modern commercial wide-body aircraft to quantitatively and qualitatively determine the sweep of transonic wings. Results from the aerodynamic shape optimization of a low-sweep wing of a modern transonic civil transport aircraft shows that it is possible to delay the drag rise of this wing to beyond Mach Number of 0.8 if the sections are redesigned. It is conceivable that future aircraft designs will be governed by the need to deliver improved performance with reduced fuel consumption. In this study, we systematically study the feasibility of designing wings with low sweep without aerodynamic or structural performance penalties. The study presented here explores the possibility of extending some commonly accepted limits related to the general layout of an efficient transonic wing. Specifically, the Mach-sweep-thickness relationships are revisited at a cursory level. Pure aerodynamic optimization of wings with varying sweeps (5 to 35 degrees) shows that the design space is relatively flat. These optimized configurations are then studied using an aerostructural optimization package along with planform variations. The aerostructural optimization reveals that the design space is again relatively flat, confirming the assumption that wings with low sweep can be effectively used as an alternative to current sweptback configurations. The results obtained from the optimization studies show that it may be possible to significantly reduce wing sweep without incurring either aerodynamic or structural penalties, especially for M ≤ 0.8 aircraft designs.