An electronic system includes a fan module, an embedded controller, an error microphone, an active noise cancellation controller, and a micro speaker module. The error microphone is configured to output an error signal by detecting the noise level during the operation of the electronic system. According to the error signal and the fan information provided by the embedded controller, the active noise cancellation controller calculates the narrow-band noises associated with the actual single-blade fundamental frequency noise and the actual BPF fundamental frequency noise generated by the fan module, and drives the micro speaker module accordingly for providing a noise cancellation signal. The error signal may be reduced to zero by adaptively adjusting the noise cancellation signal for canceling the noises generated during the operation of the electronic system.

A reference microphone for detecting noise is located under a first duct. The noise is in the form of a first plane wave in the first duct. A speaker is located on a top of the first duct. Connected to an upper part of the first duct is a second duct including an error microphone. The first plane wave in the first duct passes through an acoustic path and reaches the second duct. The error microphone detects the sound, and the speaker outputs a second plane wave with an opposite phase for canceling the first plane wave.

A box-shaped air intake silencer with vertical baffles for a gas turbine system. The box-shaped silencer has a silencer housing having opposing ends with a first end closed and a second end opened to permit passage of air. Opposing sidewalls extend between the first end and the second end with each of the sidewalls operative to receive a perpendicular flow of intake air. A silencer having vertically, spaced baffles are disposed within the housing. A first end of the baffles face the first end of the housing and a second end of the baffles faces the second end of the housing. Each of the baffles extend horizontally between the first end and the second end of the housing. The baffles receive the perpendicular flow of intake air proximate the first end of the housing and direct the intake air towards the second end of the housing for passage therethrough.

The present disclosure provides a gas turbine combustor including a combustion structure (10) having a combustor liner (14) and a flow sleeve (12). The combustor liner (14) includes inner and outer surfaces (31, 30) and defines a combustion zone (15). The gas turbine combustor further includes a plurality of hollow airfoil-shaped structures (22) affixed to the combustor liner (14) and extending radially outwardly into an airflow space (18) defined radially between the flow sleeve (12) and the combustor liner (14). Each hollow structure (22) includes at least one metering tube (26) providing acoustic communication between the combustion zone (15) and the hollow structure (22). The metering tubes (26) are detachably coupled to the combustor liner (14) for permitting interchanging of the metering tube (26) with at least one additional metering tube having at least one different dimension to effect a change in an acoustic characteristic of the hollow structure (22).

A blisk assembly for vibration dampening includes a disk portion extending circumferentially about a central axis of the blisk, a plurality of blades integrally coupled to the disk, and a piezoelectric damping ring that includes a damping ring and a plurality of piezoelectric elements coupled to the damping ring. The disk portion includes a groove configured to receive the piezoelectric damping ring. As a result of centrifugal forces applied to the piezoelectric damping ring during rotation of the blisk assembly, mechanical energy may be generated at one or more of the plurality of piezoelectric elements, which is converted to electrical energy and transmitted to another one or more of the plurality of piezoelectric elements. Accordingly, the one or more of the piezoelectric elements having received the electricity can convert the electricity to mechanical energy to provide vibration damping.

A blower and a method for decreasing eddy noise are provided. The blower includes a fan frame, a fan wheel, at least one induction element and a coil. The fan frame has in inlet and an outlet. The fan wheel is disposed in the fan frame and has a wheel hub and a plurality of fan blades connected to periphery of the wheel hub. The induction elements are fixed to the corresponding fan blades, the coil is disposed on the fan frame for driving the at least one induction element, such that the fan blade corresponding to the induction element swing back and forth to generate a vibration sound, and the vibration sound is counteracted with eddy noise generated when the fan wheel rotates. Moreover, the method for decreasing eddy noise is also provided.

A gas turbine engine is disclosed which includes a bypass passage that in some embodiments are capable of being configured to act as a resonance space. The resonance space can be used to attenuate/accentuate/etc a noise produced elsewhere. The bypass passage can be configured in a number of ways to form the resonance space. For example, the space can have any variety of geometries, configurations, etc. In one non-limiting form the resonance space can attenuate a noise forward of the bypass duct. In another non-limiting form the resonance space can attenuate a noise aft of the bypass duct. Any number of variations is possible.

Systems and methods for monitoring aerostructures are provided. In various embodiments, a method for monitoring an aerostructure may include: receiving a signal from a pressure sensor, the pressure sensor located downstream from the aerostructure; performing a time frequency analysis on the signal to calculate a power level over a range of frequencies; monitoring the power level over the range of frequencies; and determining a susceptibility to a flutter condition based on the monitoring the power level.

The driving device for providing assisted ventilation comprises an air inlet (15), an impeller (7) provided with blades (8) rotatably driven by a motor (6), and an air outlet (5), the rotation of said impeller (7) being caused by the air circulation through a duct (4) from the air inlet (15) to the air outlet (5), wherein said blades (8) of the impeller (7) are flexible, vibrating at least one of its ends by the thrust caused by said circulating air.

It reduces noise to improve user comfort.

A ducted fan of an aircraft includes a rotor-side fan and a stator-side duct that surrounds the rotor-side fan radially at the outside and defines a flow channel for air flowing via the fan. The stator-side duct has an inner wall that faces toward the rotor-side fan and which is perforated at least in certain sections. The stator-side duct has an outer wall that faces away from the fan. Between the inner wall and the outer wall of the stator-side duct, there are formed cavities which, forming sound-deadening resonators, are coupled via the perforated inner wall to the flow channel for the air flowing via the rotor-side fan. The cavities are filled, in a region which faces away from the inner wall and thus faces toward the outer wall, with activated carbon.