Air Curtain Flow Control for Aerodynamic Noise Reduction

In this paper, dual-jet planar air curtains are demonstrated to be able to successfully remove aerodynamic noise radiated from tandem rods in a crossflow. Single-jet air curtains have shown significant promise as a low noise technology but can introduce additional noise sources such as lip and mixing noise. In this work, dual-jet air curtains are shown to address these obstacles, achieving the same shielding height with a significantly lower overall system noise. Particle image velocimetry and flow visualisation methods allow the flow fields to be examined, and a numerical analysis with computational fluid dynamics to be validated. It is demonstrated that a judicious choice of flow parameters can result in the complete removal of the aerodynamic noise with almost no acoustic penalty. Further development of air curtain flow control is required to establish whether this might be a viable innovative solution as a low noise technology for landing gear noise reduction.