Advances in Wall Interference Corrections for Two-Dimensional Lifting Bodies
Simon Noel, David M. Birch, John J. Doherty, Tanmay Tipnis- Aerospace Engineering
A novel approach to correcting the effects of wall interference has been developed for low-speed closed-wall wind tunnels using a nonlinear least-squares optimization process independent of the model geometry. Potential flow singularities are used to represent the test object, and the method of images is used to represent the tunnel walls. Trust-region reflective optimization enables the locations and strengths of singularities to be determined iteratively with only wall pressure measurements as independent inputs. Results are obtained from a range of two-dimensional and three-dimensional airfoil test cases using both computational fluid dynamics simulations and wind tunnel experiments, including a NACA 0012 with deployed spoiler, a NACA 0015, a NACA 4415, and a McDonnell Douglas 30P30N high-lift configuration. The nonlinear least-squares wall-correction method is shown to demonstrate a considerable improvement over the conventional two-variable technique.