Four years ago, as a high school sophomore, I began work on an independent project that explored ways to improve the performance of high-lift systems used on the Airbus A330-300. One of the biggest challenges facing me was how to best conduct experiments to assess the performance of the different designs. In prior years, I had conducted simple research on aircraft wing design and aeroelasticity using unpowered balsa models of the aircraft being tested. To employ this same method would be unworkable for the relatively complex systems of flaps and slats required by the Airbus aircraft. I would have needed to build a larger scale model or perform wind-tunnel testing — neither of which was viable because I did not have access to equipment of the complexity required.
I turned to computational fluid dynamics (CFD) from ANSYS to perform the virtual testing required for my designs. Early models focused on relatively major modifications to the A330-300 flap system. I simulated a full-span system, a blended flap system and the standard flap system in ANSYS CFX software in takeoff and landing configurations under steady-state conditions. These virtual tests yielded valuable insight into the nature of high-lift flows, indicated that the standard system was best, and yielded the highest lift-to-drag ratio for both takeoff and landing configurations. While these simulations were relatively simple and did not yield significant results (with respect to the proposed designs), they did highlight shortcomings in the standard system that then fuelled another set of ideas.
Observation of flow separation and flap-generated vortices led to the development of designs that were specifically intended to combat these issues through flow control. Active flow control would be problematic — because of technical complexity and practicality with regard to weight and space considerations and certification regulations that require aerodynamic performance to be independent of power loss; therefore systems tested were based on passive flow control. One of the designs relied on ducts embedded within the wing box to transport high-velocity air from the leading edge to the flap housing (essentially a passive blown-flap system), with the goal of re-energizing airflow and combating recirculation in the housing. The other design used venturi tubes embedded in the flaps to generate suction near flap trailing edges to combat flow separation at the flap surface. I virtually tested these designs along with the standard system used in the first round of simulations.
These new simulations relied on a more-complex geometry that accounted for leading-edge devices (the engine nacelle/pylon assembly) and were run using a more complex grid (approximately 5 x 106 nodes vs. approximately 1 x 106 nodes for the initial tests). I also used a fully turbulent transient scheme. The results proved interesting. The separation-delay system in landing configuration narrowly outperformed the standard system. The passively-blown system was found to be promising, although in need of optimization for better results.
Using ANSYS software helped me gain insight into an industry that is often very opaque and inaccessible to those interested in learning more about it, and provided valuable experience in using professional engineering tools for research. It was instrumental in furthering my understanding of fluid physics and aerodynamic design, fueling my imagination and cementing my interest in the field for years to come.