A Comparative Study of Hardwall and Hybrid Anechoic Test Section Aerodynamics

Research is underway to evaluate the aerodynamic performance of two different wind tunnel test sections. These test sections are the hardwall test section and the hybrid anechoic test section, a novel design where the port and starboard walls are replaced by tensioned Kevlar fabric with the goal of making the walls acoustically transparent yet aerodynamically impervious. Having applications in noise reduction of wind turbines, aircraft, naval vessels, and more, the anechoic test section will benefit from a full characterization of its aerodynamic performance as compared to that of a traditional hardwall section. This characterization includes the comparison of lift data produced by airfoils in both test sections, as well as detailed measurements of and around the Kevlar walls. Deeply tied to this comparison is the consideration of the appropriate method to correct the anechoic data for the confining effects of the Kevlar walls. This report presents a new addition to the formulation of one such correction method, the panel method correction. The panel method is then compared to the conventional correction method and is shown to have higher fidelity, suggesting that it be adopted for use in full production wind tunnel