A. Hersch and B. Walker, “Effect of Grazing Flow on the Acoustic Impedance of Helmholtz Resonators Consisting of Single and Clustered Orifices,” NASA Contractor Report 3177, 1979.

has been cited by the following article:

• TITLE: Attenuation Performance of a Semi-Active Helmholtz Resonator in a Grazing Flow Duct

  AUTHORS: Xiaofeng Shi, Cheuk Ming Mak, Jun Yang

  KEYWORDS: Helmholtz Resonator; Flow Effect; Semi-Active Control

  JOURNAL NAME: Open Journal of Acoustics, Vol.3 No.1, March 29, 2013

  ABSTRACT: Side branch Helmholtz resonators (HRs) are widely used to control low frequency tonal noise in air duct system. The passive Helmholtz resonator only works effectively over a narrow frequency range around resonance frequency. Changes in the exciting frequency and temperature will decrease the noise reduction performance. Many studies have been conducted on incorporating a Helmholtz resonator with active noise control to tuning the resonance frequency of HRs. The objective of this study is to study the effect of flow on the semi active Helmholtz resonator for duct noise control. Owing to a low Mach number air flow, the discontinuity condition at the joint is analytically formulated according to the conservation of the momentum and mass of air flow. Based on the transfer function at the junction, a controller function is proposed to tune the semi-active Helmholtz resonator under flow condition.