One of the most efficient, cost effective and widely used approaches to reduce the tonal signature of aeronautic engine noise is the so-called liners-structures located in the internal walls of the nacelle (the external structure of the motor) that form an acoustic treatment. In the research project called "Silent Aircraft", funded by FINEP and Emb

New microphone mountings designed to reduce flow noise by recessing the microphones and covering the cavities will also be described, and their flow noise levels compared to flush-mounting the microphones. Typical honeycomb core, perforated face-sheet liner samples were tested at different flow speeds at FLIR. Results were fed to multiple, previous

You may be surprised to find that the control of the sound of a room is not really very complicated and can usually be accomplished with inexpensive materials.The paper deals with the setting up and test flights of a fuel cell general aviation aircraft fuelled by hydrogen. A general explanation of the design activities is first presented in conjunc

So much has changed. When you get older, you look back on tensions and grievances and have another perspective on it. I think our relationship now is better than it's ever been. I would even describe it as great.Now that he’s staying on the sidelines while his bandmates revive their incendiary songs with help from Chuck D and B-Real during a

In this paper, the acoustic impedance of a liner is educed by a novel semi-analytical inverse technique. The liner sample is placed flush with the solid walls in a rectangular duct with grazing flow. The technique uses complex acoustic pressure measured at four positions at the wall of the duct, upstream and downstream of the lined section, and edu