Elastomeric Actuators on Airfoils for Aerodynamic Control of Lift and Drag

This paper investigates and characterizes the aerodynamic performance of a unique platform of airfoils with inflatable, elastomeric actuators. By controlling the inflation of stretchable and tough pneumatic bladders of silicone at specific locations of threedimensionally printed airfoils, experiments demonstrate it is possible to manipulate aerodynamic lift and drag. Measurements on morphable airfoils carried out in a smallscale wind tunnel at low Reynolds number include coefficients of lift, coefficients of drag, and stalling angles. Experiments at a constant angle of attack in a wind tunnel show that a pseudo flap deployed on the bottom portion of an airfoil near the trailing edge can increase lift by a factor of 20% 300%. Another design with an inflatable region near the leading edge of an airfoil increases lift and the stalling angle at high angles of attack (>12°). This work also presents general predictions for the performance of each geometric configuration using two-dimensional (2D) computational fluid dynamics-based (CFD) simulations. Comparisons between simulations and experiments verify the efficacy of the outlined approach. This work is the frrst to describe the dynamic (i.e., not binary states of being inflated/deployed and deflated/undeployed) fluid-soft material interactions for both lift and drag of inflatable actuators embedded in stiff structures.