Experimental approach to performance improvement of Helmholtz resonators under airflow conditions

This study investigates the performance improvement of Helmholtz resonators under airflow condition by using viable models. These models are based on two simple, attractive approaches: one is to change the shape of the cross section of the resonator’s neck and the other is to install an air dam at the front of the neck of the resonator. The performance of the proposed models based on these approaches was evaluated by analytic and experimental studies. The results revealed that the proposed approaches give one of the novel solutions to designing improved resonators under various flow conditions. Through a computational fluid dynamics (CFD) analysis, flow characteristic variables such as mean flow velocity and turbulence kinetic energy were investigated for the proposed models. Also, the noise reduction performance of the models based on the proposed approaches under airflow conditions was analyzed by experiments. Furthermore, the correlation of the flow characteristic variables with noise reduction performance was investigated for use as a design guideline for resonators under various flow conditions.