Numerical Simulations of Mixing Enhancement in Subsonic Jet Using High-Momentum Synthetic Jets

High-momentum synthetic jets have been used to enhance the mixing of a subsonic round jet with ambient air. The enhanced mixing processes are studied numerically to reveal jet mixing enhancement mechanisms. A parametric study has been carried out focusing on the effects of synthetic jet nozzle outlet diameter and maximum blowing jet momentum on penetration depth, interaction area, and counter-rotating vortices pair vorticity. Results show that high-momentum synthetic jets significantly affect the subsonic round jet. The centerline length of the primary jet high-temperature zone is reduced by up to 75% with the presence of synthetic jets. The induced streamwise vortices and the primary jet flapping resulting from synthetic jets are the key mixing mechanism. Jet mixing enhancement is related to the interaction area and the synthetic jet maximum momentum, which is the key parameter in jet mixing.