The elusive cost function for tuning adaptive Helmholtz resonators
Date
2006
Authors
Singh, S.
Hansen, C.
Howard, C.
Editors
Terrance McMinn,
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Conference paper
Citation
Proceedings, Australian Acoustical Society, New Zealand Acoustical Society : First Australasian Acoustical Societies' Conference : Acoustics 2006 : noise of progress, Clearwater Resort, Christchurch, New Zealand, 20-22 November 2006 / Terrance McMinn (ed.): pp. 75-82
Statement of Responsibility
Sarabjeet Singh, Colin H. Hansen and Carl Q. Howard
Conference Name
Australasian Acoustical Societies' Conference (1st : 2006 : Christchurch, New Zealand)
Abstract
One of the problems associated with the use of Helmholtz resonators to control tonal noise propagation inside a pipe or duct is that any slight frequency changes in the tonal noise as a result of environmental changes or load changes on the device generating the noise will severely compromise the performance of the resonator. Thus, it is desirable to use an adaptive resonator whose volume or neck length can be adjusted to maintain optimal tuning as the excitation frequency or environmental conditions change. The ideal cost function would be a measure of the sound power propagating down the duct so the control system could minimise this quantity by driving motors that change the geometry of resonator. In practice, it is highly desirable to have available a self-contained adaptive resonator that does not need any external inputs or measures of quantities outside the resonator package. A cost function based on pressure measurements in the resonator, which corresponds to sound power in the duct has been found and verified experimentally and numerically. The effect of resonator damping on the cost function and a method to correct for the effect is also discussed. Copyright © (2006) by the Australian Acoustical Society.