Using vibration to reduce drag.
(www.carthrottle.com)https://www.carthrottle.com/post/can-you-improve-a-cars-aerodynamics-by-making-it-vibrate/This follows experiments in the lab where piezoelectric actuators were used to induce traveling waves along the surface of an airfoil. It was found that low amplitude traveling waves between 6-10hz would destructively interfere with vortex shedding. This reduced drag and allowed greater AoA.
