体積可変共鳴器による管路の準能動消音

抄録

A pressure attenuating system for a flow in a pipe whose compressor has a varying rotational speed was built. This system is composed of a Helmholtz resonator whose cavity's volume is automatically controlled by a personal computer such that the system retains the antiresonance. The steady state response and the transient response are investigated theoretically and experimentally by making use of the sinusoidal sound. When the exciting frequency shifts slowly, the sound pressure is reduced by 20 dB. When the tracking has a delay, it is possible that the system may pass through the resonance.