Aerodynamic Assessment of a Control Strategy Based on Twist Morphing Wing in a Flying Wing Aircraft

Wing smarting and eliminating conventional control surfaces are fundamental parameters for improving aircraft aerodynamic performance in future aviation. Twist is a well-known tool that, along with the development of morphing technology, can play a crucial role in controlling next-generation aircraft. However, wing twisting with a control approach requires many aerodynamic studies, particularly at the high aft-swept angle; this is more noticeable in the flying wing configuration. In this paper, a control strategy based on twist morphing has been evaluated aerodynamically at the Swing, a flying wing configuration. Extraction of aerodynamic coefficients and flow field on the wing have been performed using the computational fluid dynamics (CFD) method in an incompressible flight regime. To comprehensively cover the control needs, two control concepts have been introduced, called independent and nonindependent twist. Within the concept of independent twist, a co-oriented twist arrangement (Co-OTA) and counteroriented twist arrangement (Cun-OTA) are applied to the wings, which are used to produce pitching and rolling moments, respectively. The results show these control arrangements have high efficiency at low angles of attack (AoAs), but as the AOA increases, their aerodynamic performance will gradually decrease. In this regard, a significant challenge for Cun-OTA is producing the yawing moment during roll maneuvering. Attempts to solve this problem have led to the idea of a compound twist arrangement (CTA). The existence of a control arrangement to generate yawing moment is beyond the capacity of the independent twist concept. The nonindependent twist has been introduced as a solution to this issue.

Conventional control surfaces have various weaknesses, one of the most important of which is the unfavorable effects on aerodynamic efficiency; the reduction of aerodynamic efficiency leads to a drop in flight endurance and an increase in fuel consumption. At a step forward, with the approach of wing smarting and morphing technology, the tasks of conventional control surfaces can be delegated to the wing itself. Therefore, it will be possible to remove the control surfaces and integrate the wing. In this article, according to the mentioned approach, an attempt was made to introduce a control strategy based on the geometric twist. In this strategy, the value and direction of the twist applied to each wing produces a specific control arrangement. Control arrangements (three types of arrangements) are involved in producing longitudinal and lateral and modified lateral moments. The results indicate that the use of twisting in aircraft control is efficient for a wide range of flight conditions, and this capability exists to be used in the next generation of aircraft. In this way of control, challenges are deliberately related to the design of the operating mechanism, safety issues, and weight.