An extended neck versus a spiral neck of the Helmholtz resonator

Chenzhi Cai, Cheuk Ming Mak, Xiaofeng Shi

Research output: Journal article publicationJournal articleAcademic researchpeer-review

73 Citations (Scopus)


An extended neck or a spiral neck takes the place of the traditional straight neck of the HR. The acoustic performance of the HR with these two types of necks is analyzed theoretically and numerically. The length correction factor is introduced through a modified one-dimensional approach to account for the non-planar effects that result from the neck being extended into the cavity. The spiral neck is transformed to an equivalent straight neck, and the acoustic performance is then derived by a one-dimensional approach. The theoretical prediction results fit well with the Finite Element Method (FEM) simulation results. Without changing the cavity volume of the HR, the resonance frequency shows a significant drop when the extended neck length or the spiral neck length is increased. The acoustic characteristics of HRs with these two different neck types have a potential application in noise control, especially at low frequencies within a constrained space.
Original languageEnglish
Pages (from-to)74-80
Number of pages7
JournalApplied Acoustics
Publication statusPublished - 1 Jan 2017


  • Extended neck
  • Helmholtz resonator
  • Noise control
  • Spiral neck

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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