Experimental closed-loop control of flow separation on a simple hinged flap using extremum-seeking

Adaptive closed-loop control of flow separation over a non-slotted flap is proposed in this paper. It is implemented through optimization of either the forcing frequency or the oscillatory momentum coeffcient. First, to optimize the forcing frequency, a modified extremum-seeking scheme involving the local estimation of the equilibrium map curvature and a fuzzy regulator is developed. On this application, the modified scheme shows faster convergence rate than the classic one. Secondly, to optimize the oscillatory momentum coeffcient, a modified slope-seeking scheme is proposed. It involves a fuzzy-logic regulator to compensate the equilibrium map local gradient variations and this enables faster convergence rate than the classic slope-seeking scheme.