A system for use in an aircraft or other system in an ambient airflow includes a body defining a cavity having an opening exposed to ambient airflow, with a cavity interface defined by body structure surrounding the opening. The cavity interface includes a cavity floor opposite the cavity opening, a leading edge facing away from the ambient airflow, a trailing edge facing the airflow, and a rear wall extending between the trailing edge and the cavity floor. A panel of sound-absorbing material is attached to and covers substantially all of the surface area of the rear wall of the cavity, and minimizes emanation of a predetermined range of audible sound frequencies from the cavity. The system may include an elongated serrated element connected to body and extending along the leading edge and arranged flush with the leading edge.

A manufacturing method of an abradable coating consisting of depositing, on a substrate surface a filament of a thermosetting material while providing both a relative displacement between the substrate and the filament along a predetermined deposition path and solidification of the filament in order to create a three-dimensional scaffold of filaments, consisting of superimposed layers of which the filaments of a given layer are not contiguous and can be oriented differently from those of an adjacent layer, so as to confer upon it acoustic wave absorption properties, the thermosetting material being a thixotropic mixture free of solvent and consisting of a polymer base and a cross-linking agent in a weight ratio of a polymer base to a cross-linking agent comprised between 1:1 and 2:1, and of a flowing component, typically a petroleum jelly present between 5 and 15% by weight of the total weight of the thixotropic mixture.

A sound attenuating baffle device has a baffle casing supported within a duct such that a boundary wall of the baffle device is oriented in the flow direction from the leading end to the trailing end of the baffle casing. The baffle casing includes a sound attenuating structure therein, and a trailing member protruding outwardly beyond the trailing end of the baffle casing towards a free trailing edge of the trailing member which is non-linear in profile. As compared to a continuous, straight trailing edge as found on most silencer outlets, a non-linear profile, for example a V-shaped or saw-toothed edge, improves the flow distribution along the height of the baffle or perimeter of the centerbody. The distribution of airflow across the resulting extended tail edge represents an improvement in the flow recovery.

A compressor including a shaft, a flange to support shaft, and a muffler to reduce noise generated in a compression chamber of the compressor. The flange including a plurality of noise reductions units each of which is formed to have a different volume and at least a portion of the noise reduction unit is covered by the muffler.

Provided is a soundproof structure body including an opening member that forms an opening tube line having a cross-sectional area S, and at least two resonance structures for sound waves that are installed inside the opening tube line, and in a case where a cross-sectional area of the resonance structure is defined as Si, a width thereof is defined as di, an interval between the two resonance structures is defined as L, an impedance of the two resonance structures is defined as Zi, and a synthetic acoustic impedance is defined as Zc, a condition of Expression (1) is satisfied at a resonance frequency f0 at which a theoretical absorption value At is a maximum value. This soundproof structure body can realize high absorption using a plurality of resonance structures.
At(f0, L, S, Si, di, Zi)>0.75  (1), Here, L>0, S>0, Si (i=1, 2)>0, di (i=1, 2)>0

One aspect of the present disclosure provides a muffler including an exhaust pipe and a space forming member. The exhaust pipe has a cylindrical shape having a flow passage inside through which exhaust gas passes. The space forming member forms closed spaces between itself and the exhaust pipe, the closed spaces being branched from the flow passage and adjacent to the flow passage. Each of the closed spaces and the flow passage communicate with one another via a single communication hole.

A body dryer includes an airflow generator to generate a flow of air, an inlet to pass air from the surroundings to the airflow generator, an outlet to vent the air from the airflow generator, a body, and a movable bar, the bar supported by the body. A drive assembly is provided between the body and the bar, the bar movably driven relative to the body. A noise cancellation device is provided to cancel or reduce noise in at least one of the airflow generator and the drive assembly.

Exhaust systems for a vehicle are provided. In one example, an exhaust system includes a muffler, a first exhaust outlet pipe fluidly coupled to a first outlet of the muffler, a second exhaust outlet pipe fluidly coupled to a second outlet of the muffler, a bypass duct fluidly coupled to a third outlet of the muffler, and a combined X-Y shaped intersection at which the first exhaust outlet pipe, the second exhaust outlet pipe, and the bypass duct are fluidly coupled to each other.

A silencer comprises a main air guide tube provided with an air guide channel; the main air guide tube comprises an air inlet end and an air outlet end; both ends of an assistant air guide tube are connected with an outer wall of the main air guide tube, and the assistant air guide tube comprises a guide section and a reflux section; the guide section is provided with an air inlet, and the air inlet is communicated with the air guide channel; the reflux section is provided with an air outlet, and the air outlet is communicated with the air guide channel.

Systems and methods are provided for a combined spark arrestor and muffler assembly. In one example, a system may include a combined housing, the combined housing including a spark arrestor portion including a plurality of stator fins, and a muffler portion including acoustic packing, the muffler portion fluidically coupled to the spark arrestor portion via a first sliding joint and a second sliding joint. In this way, a single component of a vehicle exhaust system may reduce sparks and/or carbon deposits in exhaust gas, while also reducing exhaust noise.