Normal Shock Wave/Turbulent Boundary Layer Interaction Control using “Smart” Piezoelectric flap actuators improved results. NOMENCLATURE E Young’s Modulus M Mach number t thickness Subscripts n normal s substrate properties Abbreviations

摘要

This paper looks at active control of the normal shock wave/turbulent boundary layer interaction (SBLI) using smart flap actuators. The actuators are manufactured by bonding piezoelectric material to an inert substrate to control the bleed/suction rate through a plenum chamber. The cavity provides communication of signals across the shock, allowing rapid thickening of the boundary layer approaching the shock, which splits into a series of weaker shocks forming a lambda shock foot, thus reducing wave drag. Active control allows optimisation of the interaction, as it would be capable of either positioning the control region around the original shock position using a series of unimorph flaps or fixing the shock position by controlling the rate of mass transfer. The actuators are modelled using classical composite material mechanics theory, namely analysis of a laminate with a uniform cross section. Furthermore a finite element modelling program (ANSYS 6.0) was used to produceimproved results.