1. Technical Field
This disclosure relates generally to an acoustic panel and, more particularly, to an acoustic panel for attenuating noise generated during, for example, operation of a turbine engine.
2. Background Information
A gas turbine engine may include an acoustic sandwich panel for attenuating noise generated during turbine engine operation. A typical acoustic sandwich panel includes a honeycomb core bonded between a solid face sheet and a perforated face sheet. The honeycomb core includes a plurality of resonating cavities. The honeycomb core has a thickness sized to tune the resonating cavities to a specific target frequency of noise to be attenuated. As a result, noise energy reflected by the acoustic sandwich panel interacts with noise energy traveling towards the panel. Differences in phase between the noise energy in an acoustic field adjacent the perforated face sheet may enable the reflected noise energy to destructively interfere with and attenuate the noise energy traveling towards the acoustic sandwich panel.
Modern engine designs may require acoustic sandwich panels to attenuate noise energy with relatively low frequencies while utilizing substantially the same or less space than previous panels. Attenuating low frequencies, however, may increase the thickness of the honeycomb core and, thus, the thickness of the acoustic sandwich panel. There is a need in the art therefore for an improved noise attenuating acoustic panel.