Effective Range of Micro and Synthetic Jets for Flow Control

Abstract

Effectiveness of two-dimensional synthetic jet is studied using numerical simulations. A Navier-Stokes (NS) solver for moving and deforming meshes has been modified to investigate numerically the diaphragm-driven flow in and out of two synthetic jet cavity geometries. Compressible flow simulations are required for rarefied gas flows to accurately predict the micro flow field. The solver is modified to accommodate slip wall boundary condition proposed in literature for micro scale flow problems. The piezoelectric-driven diaphragm of the cavity is modeled in a realistic manner as a moving boundary to accurately compute the flow inside the jet cavity. The primary focus of the proposed paper will be on the analysis of the design space determined by the geometric and flow-type design variables that identify the effectiveness of the synthetic jet by means of the orifice jet velocity and local jet momentum rate. The design variables are the membrane oscillation frequency (f), membrane oscillation amplitude (A), orifice width (d), and membrane width (W). The present computations for jet discharging into quiescent medium reveal that these variables have determining effects on the flow control parameters, which are the jet exit velocity, local momentum rate, as well as vortex shedding from the orifice.