科研之友
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摘要
Low frequency cavity noise can be reduced by coupling tuned Helmholtz resonators to the acoustic cavity. Modeling several resonators along with the cavity is computationally intensive due to the requirement of fine meshing around the resonators. The resonator modeling can be simplified by specifying its free-field reactance at the mounting locations on the boundaries of the acoustic cavity; while a simple formula for reactance exists for single orifice resonators, such a formula is not available for a multi-orifice resonator, which is the subject of investigation in this paper. A design relation between the first natural frequency of a single orifice resonator and a multi-orifice resonator, whose total orifice area equals that of the single orifice, has been developed. This is shown to be independent of the shape/size of the orifice as well as the resonator cavity; experiments have been done to validate the numerical simulations. A new end correction formula, for the orifice lengths of multi-orifice resonators, has been derived from this design relation. This formula has been used to calculate the reactance analytically. Comparison with numerically generated reactances, for various resonator geometries, show excellent agreement.
- 出版日期2015-2
