An aircraft fairing includes a fairing body having an exterior fairing wall and at least one wheel bin. The at least one wheel bin has a side wall extending from an opening in the exterior fairing wall to an end wall. The side wall and the end wall define a cavity of the at least one wheel bin in fluid communication with the opening in the exterior fairing wall. An acoustic resonator is mounted to an outer surface of the side wall of the at least one wheel bin and is in fluid communication with the cavity. The acoustic resonator has a resonant frequency substantially similar to a cavity modal frequency of the at least one wheel bin at an aircraft flight condition.

A first ventilation duct line has a first portion having a first sectional area, a second portion having a second sectional area larger than the first sectional area, and a third portion having an inclined inner face connecting the first portion and the second portion to each other. Further, there is a second ventilation duct line having an opening portion positioned on an inner side of the first portion of the first ventilation duct line.

A first ventilation duct line has a first portion having a first sectional area, a second portion having a second sectional area larger than the first sectional area, and a third portion having an inclined inner face connecting the first portion and the second portion to each other. Further, there is a second ventilation duct line having an opening portion positioned on an inner side of the first portion of the first ventilation duct line.

An acoustic structure includes a plate and at least one acoustic scatterer having a resonant frequency and coupled to a side of the plate. The at least one acoustic scatterer has an opening, a first channel and a second channel. The first channel has a first channel open end and a first channel terminal end with the first channel open end being in fluid communication with the opening. The second channel has a second channel open end and a second channel terminal end with the second channel open end being in fluid communication with the opening. The first channel terminal end and the second channel terminal end are separate from one another.

An acoustic structure includes a plate and at least one acoustic scatterer having a resonant frequency and coupled to a side of the plate. The at least one acoustic scatterer has an opening, a first channel and a second channel. The first channel has a first channel open end and a first channel terminal end with the first channel open end being in fluid communication with the opening. The second channel has a second channel open end and a second channel terminal end with the second channel open end being in fluid communication with the opening. The first channel terminal end and the second channel terminal end are separate from one another.

A versatile metamaterial reflector is constructed of at least one pair of first and second reflectors each having a frequency-dependent phase shifting of a reflected waveform but together providing, between them, a constant phase difference. As few as two different types of reflectors (for example, a zero and relative pi radian reflector) are used to construct a variety of metamaterial reflectors.

A sound insulation device contains at least one rigid support element and at least one elastic membrane element. The rigid support element contains at least one support grid containing a plurality of cells. The elastic membrane element is arranged on the support grid. The sound insulation device is configured to block at least partially acoustic energy transmission at a frequency range of 60 Hz to 500 Hz. The sound insulation device exhibits a negative effective mass below a resonance frequency, where the resonance frequency is given by:

[00001]${\omega }_0=\frac{4\pi \delta }{A}\sqrt{\frac{E}{\rho \left(1-{\vartheta }^2\right)}},$

where A is a pore size of the support grid spun by the membrane element, δ is a thickness of the membrane element, E is an elastic modulus of the membrane element, ρ is a density of the membrane element, and ϑ is a Poisson ratio of the membrane element. The elastic modulus E of the membrane element is ≥8 MPa.

A sound insulation device contains at least one rigid support element and at least one elastic membrane element. The rigid support element contains at least one support grid containing a plurality of cells. The elastic membrane element is arranged on the support grid. The sound insulation device is configured to block at least partially acoustic energy transmission at a frequency range of 60 Hz to 500 Hz. The sound insulation device exhibits a negative effective mass below a resonance frequency, where the resonance frequency is given by:

[00001]${\omega }_0=\frac{4\pi \delta }{A}\sqrt{\frac{E}{\rho \left(1-{\vartheta }^2\right)}},$

where A is a pore size of the support grid spun by the membrane element, δ is a thickness of the membrane element, E is an elastic modulus of the membrane element, ρ is a density of the membrane element, and ϑ is a Poisson ratio of the membrane element. The elastic modulus E of the membrane element is ≥8 MPa.

Resonating patch for acoustic treatment comprising a resonant plate, a transducer and an electrical circuit electrically connected to the transducer, the resonant plate comprising a peripheral strip extending along the perimeter of the resonant plate.

The patch comprises cutouts together defining deformable lamellae having at least one end connected to the peripheral strip.

Resonating patch for acoustic treatment comprising a resonant plate, a transducer and an electrical circuit electrically connected to the transducer, the resonant plate comprising a peripheral strip extending along the perimeter of the resonant plate.

The patch comprises cutouts together defining deformable lamellae having at least one end connected to the peripheral strip.