Improving 3D Synthetic Jet Modeling in a Crossflow

Abstract

Three different circular synthetic jet modeling inlet conditions are studied for a turbulent crossflow. The study examines the differences when modeling the whole SJA, neck-only or jet-slot-only under constant actuation frequency (f = 300 Hz) and crossflow blowing ratio (CB = 0.67). Phase-averaged and time-averaged results reveal that both whole SJA and neck-only methods generated nearly identical flow fields. For the neck-only case, a notable reduction in computational cost is achieved through the implementation of an analytical jet profile. The jet-slot-only method, on the other hand, introduces reversed flow during the ingestion cycle, leading to the injection of false-momentum into the crossflow. However, the false-momentum primarily affects the flow immediately downstream of the jet exit, with the boundary layer profile recovering rapidly. A parametric study highlights the importance of maintaining a volume ratio less than 1 of ingested to modeled neck volume to prevent the creation of false-momentum.