Measurements of the acoustic attenuation by single layer acoustic liners constructed with simulated porous honeycomb cores

An experimental investigation into the acoustic suppression by single layer liners with simulated porous honeycomb cores was conducted. The porous honeycomb was simulated by means of porous partitions whose resistance was varied between zero (no partitions) and infinity (impervious partitions). In addition to the resistance of the porous partitions, variation in the face sheet resistance was also included in the test matrix. A wave tube test apparatus was designed, fabricated and set up. An array of 16 transducers was used to measure the acoustic field in the wave tube. This allowed measuring of the acoustic attenuation data for the different liner configurations. These data showed that for a given value of the face sheet resistance, the variation in the resistance of the porous honeycomb had a significant impact on the acoustic attenuation.