Spatially Distributed Forcing and Jet Vectoring with a Plasma Actuator

Abstract

volume momentum balance was used. By shaping the buried electrode along the span of the actuator, the local volume of plasma generated can be controlled, which is related to the local body force. Pressure measurements were takenintheboundarylayerbehindtheactuatortocalculatethemomentumimpartedtothe flowatvariousspanwise locations corresponding to different electrode widths. Particle image velocimetry data were then used to show that spatially varying, steady jets could be created with the use of only one actuator by varying the width of the buried electrode in a quiescent flow. The angle of the jet created, relative to the dielectric, by a plasma synthetic jet is also investigated. By pointing two plasma actuators at each other, an inverted impinging jet can be created as a result of the two independent jets colliding. By altering the strength of one of the jets relative to the other, the angle of separation can be changed. Particle image velocimetry data were taken to show the effects of altering the voltage (strength)appliedtooneoftheactuatorsrelativetotheother.Itwasfoundthat,withthismethod,jetvectoringcould beachieved.Theangleofthejetcouldbecontrolledafull180degthroughsmallchangesinthevoltageappliedtothe electrodes, also in a quiescent flow. Nomenclature D = diameter FB = body force FS = shear force P = power qd;off = dynamic pressure downstream of the actuator (0.035 m) with the plasma off qd;on = dynamic pressure downstream of the actuator (0.035 m) with the plasma on Re = Reynolds number St = Strouhal number U = freestream velocity ud;off = velocity downstream of the actuator (0.035 m) with the plasma off ud;on = velocity downstream of the actuator (0.035 m) with the plasma on W = waviness amplitude � = angle of jet measured counterclockwise � V = voltage differential between exposed electrodes relative to ground � = wavelength