Abstract: An acoustic attenuation structure for a gas turbine engine includes a periodic structure having a first unit cell, the first unit cell having a first central body and a first axial tube disposed on the first central body and a second axial tube disposed on the first central body, opposite the first axial tube, each of the first axial tube and the second axial tube being in fluid communication with one another through the first central body.

Abstract: A compressor has an inlet port and a discharge port. The discharge port communicates into a resonator chamber. The resonator chamber includes a first stage resonator array and a second stage resonator array downstream of the first stage resonator array with a connecting passage intermediate the first and second resonator array. Each of the resonator arrays includes a pair of spaced resonator arrays sub-portions, with each of the sub-portions including a plurality of cells extending into a housing member, and have a bottom wall and an open outer wall communicating with the flow passage, with a plurality of orifices extending into each of the cells. The orifices have a smaller diameter than a hydraulic diameter of the cells.

Abstract: An acoustic attenuation structure for a gas turbine engine includes a periodic structure having a first unit cell, the first unit cell having a first central body and a first axial tube disposed on the first central body and a second axial tube disposed on the first central body, opposite the first axial tube, each of the first axial tube and the second axial tube being in fluid communication with one another through the first central body.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A section for a gas turbine engine includes a rotating structure, a stationary structure, and a flow guide assembly arranged generally between the rotating structure and the stationary structure. A flow path is defined between the flow guide assembly and one of the rotating structure and the stationary structure. The flow guide assembly includes a plurality of apertures configured to disrupt acoustic waves of air in the flow path. A seal is configured to establish a sealing relationship between the rotating structure and the stationary structure, and wherein an inlet to the flow path is adjacent the seal. A gas turbine engine and a method of disrupting acoustic waves in a flow path of a gas turbine engine are also disclosed.

Abstract: Acoustic treatments for components of gas turbine engines are described. The acoustic treatments include an acoustic resonator having a backing chamber defining a respective volume and a neck arranged relative to the backing chamber and defining an opening, wherein the neck has a length and a cross-sectional area. The acoustic resonator cell satisfies the following relationships: (1) l/L=0.2-0.8, where l is a length of the neck and L is a depth of the backing chamber and (2) a/A=0.02-0.20, where a is a cross-sectional area of the neck and A is a cross-sectional area of the backing chamber.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: Acoustic treatments for components of gas turbine engines are described. The acoustic treatments include an acoustic resonator having a backing chamber defining a respective volume and a neck arranged relative to the backing chamber and defining an opening, wherein the neck has a length and a cross-sectional area. The acoustic resonator cell satisfies the following relationships: (1) l/L=0.2-0.8, where l is a length of the neck and L is a depth of the backing chamber and (2) a/A=0.02-0.20, where a is a cross-sectional area of the neck and A is a cross-sectional area of the backing chamber.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A compressor has an inlet port and a discharge port. The discharge port communicates into a resonator chamber. The resonator chamber includes a first stage resonator array and a second stage resonator array downstream of the first stage resonator array with a connecting passage intermediate the first and second resonator array. Each of the resonator arrays includes a pair of spaced resonator arrays sub-portions, with each of the sub-portions including a plurality of cells extending into a housing member, and have a bottom wall and an open outer wall communicating with the flow passage, with a plurality of orifices extending into each of the cells. The orifices have a smaller diameter than a hydraulic diameter of the cells.

Abstract: A compressor has a housing assembly having a plurality of ports including a suction port and a discharge A male rotor is mounted for rotation about an axis. A female rotor is enmeshed with the male rotor and mounted in the housing for rotation about an axis for drawing a flow from the suction port, compressing the flow, and discharging the compressed flow through the discharge port. A cavity group is between the discharge port and the male rotor and female rotor. The cavity group has a first member separating a plurality of cells and a foraminate cover member atop the first member.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A nacelle assembly according to an exemplary aspect of the present disclosure includes, among other things, a core nacelle defined at least partially about a core engine, a fan nacelle mounted at least partially around the core nacelle to define a fan bypass flow path, and a variable area fan nozzle in communication with the fan bypass flow path. The variable area fan nozzle has a first fan nacelle section and a second fan nacelle section downstream of the first fan nacelle section. The first fan nacelle section and the second fan nacelle section are axially movable relative to one another to define an auxiliary port to vary a fan nozzle exit area and adjust fan bypass airflow. The auxiliary port is defined between the first fan nacelle section and the second fan nacelle section. The first fan nacelle section comprises a first acoustic system which provides an acoustic impedance configured to attenuate a noise characterized by a leading edge of the second fan nacelle section.

Abstract: A section for a gas turbine engine includes a rotating structure, a stationary structure, and a flow guide assembly arranged generally between the rotating structure and the stationary structure. A flow path is defined between the flow guide assembly and one of the rotating structure and the stationary structure. The flow guide assembly includes a plurality of apertures configured to disrupt acoustic waves of air in the flow path. A seal is configured to establish a sealing relationship between the rotating structure and the stationary structure, and wherein an inlet to the flow path is adjacent the seal. A gas turbine engine and a method of disrupting acoustic waves in a flow path of a gas turbine engine are also disclosed.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A compressor (20; 600) comprising: a housing assembly (22) having a plurality of ports including a suction port (24) and a discharge port (26); a male rotor (30) mounted for rotation about an axis (500); a female rotor (32) enmeshed with the male rotor and mounted in the housing for rotation about an axis (502) for drawing a flow from the suction port, compressing the flow, and discharging the compressed flow through the discharge port; a cavity (120, 122; 620, 622, 624, 626) group (116, 118; 612, 614, 616, 618) between the discharge port and the male rotor and female rotor, the cavity group comprising: a first member (124, 80; 682, 680, 630, 632) separating a plurality of cells; a foraminate cover (130, 132; 640, 642, 644, 646) member atop the first member.

Abstract: A fan section for a gas turbine engine according to an example of the present disclosure includes, among other things, a fan rotor having fan blades, and a plurality of fan exit guide vanes positioned downstream of the fan rotor. The fan rotor is configured to be driven through a gear reduction. A ratio of a number of fan exit guide vanes to a number of fan blades is defined. The fan exit guide vanes are provided with optimized sweep and optimized lean.

Abstract: A nacelle assembly according to an exemplary aspect of the present disclosure includes, among other things, a core nacelle defined at least partially about a core engine, a fan nacelle mounted at least partially around the core nacelle to define a fan bypass flow path, and a variable area fan nozzle in communication with the fan bypass flow path. The variable area fan nozzle has a first fan nacelle section and a second fan nacelle section downstream of the first fan nacelle section. The first fan nacelle section and the second fan nacelle section are axially movable relative to one another to define an auxiliary port to vary a fan nozzle exit area and adjust fan bypass airflow. The auxiliary port is defined between the first fan nacelle section and the second fan nacelle section. The first fan nacelle section comprises a first acoustic system which provides an acoustic impedance configured to attenuate a noise characterized by a leading edge of the second fan nacelle section.