Comparative Investigation of an Over-the-Wing Engine Configuration with Hybrid Laminar Flow Control

The present work performs a preliminary comparative study of two long-range aircraft configurations featuring future airframe and propulsion technologies with two different engine allocation options. Over-the-wing and under-the-wing configurations are being evaluated as hypothetical options for next-generation, more sustainable aircraft. These designs incorporate cutting-edge technologies such as hybrid laminar flow control, advanced materials, load alleviation, and ultra-high bypass ratio engines. A multi-fidelity framework used for the comparative study is characterized by low-fidelity aircraft sizing and performance modules, medium-fidelity airfoil design, and high-fidelity aerodynamic and structural analysis modules. A focus is given to the aerodynamic assessment of hybrid laminar flow control technology to determine the potential benefits and drawbacks of the over-the-wing configuration in the context of more efficient airframe capabilities. Several computational fluid dynamics analyses were performed to assess the aerodynamic performance of each configuration. Preliminary research outcomes suggest that the more conventional under-the-wing engine presents a more promising configuration, leading to a reduction of about 13% of the cruise drag with respect to the over-the-wing engine setup. Different aspects are discussed as potential solutions to improve the efficiency of the over-the-wing engine for further and more detailed assessments.