Trailing edge actuation for a bluff body at moderate yaw optimized with a genetic algorithm

Abstract

This experimental work is conducted to manipulate the wake to reduce aerodynamic drag using the actuations on the trailing edges of a bluff body at a yaw angle of 10°. Two loudspeakers are separately installed into the vertical trailing edges of the vertical base, creating a zero-net mass-flux jet through vertical slots. A maximum drag reduction of 2% and 1.5% is produced by the single actuation on the windward and leeward side, respectively. When the genetic algorithm is introduced to optimize the actuations on both sides, a drag reduction of 7% is obtained. Thus, the energy efficiency of the entire control system is greatly improved by 80% compared to the best single actuation. The underlying flow mechanism behind the effective parameters is proposed according to the analyses of the drag spectra and the hot-wire data measured with and without control. The genetic algorithm provides a promising optimization strategy for the better control performance of trailing edge actuation on a yawed bluff body. Furthermore, this strategy may have the engineering potential to reduce the drag of ground transport vehicles for a large range of operating conditions. Therefore, this research is expected to save energy consumption and improve traveling safety for the aerodynamic control of vehicles.