Evaluation of Inner–Outer Problem Coupling in Low-Order Aerodynamic Models

Low-order and simplified methods are an important tool in the design and study of novel aircraft, propellers, and wind turbines. In particular, these tools are helpful at the early stages to confine and narrow a design space and inform selective high-fidelity numerical testing and experiments. Therefore, improving these approaches and quantifying their limitations is useful to research and development efforts. One core assumption leveraged in many applications is the mapping from 3D influences (downwash, effective angle of attack etc), to 2D coefficients of drag and occasionally also lift (in the case of non-linear lifting line theory). The present work utilizes computational fluid dynamics simulations of various rectangular wing configurations and matching 2D simulations in order to examine the limitations of this mapping. Simulations are performed of a NACA0012 test case with available experimental results. Using the available data, the relationship between sectional properties of the 3D solution and the most similar 2D solutions is examined. Furthermore, a framework to compare the accuracy of the single parameter inner-outer problem mapping is presented.