Abstract: An assembly is provided for rotational equipment. This assembly includes a stationary structure, a rotating structure rotatable about an axial centerline, and a non-contact seal assembly. The non-contact seal assembly is configured to substantially seal a gap between the stationary structure and the rotating structure. The non-contact seal assembly includes a seal shoe configured to sealingly engage the rotating structure axially along the axial centerline.

Abstract: An assembly is provided for rotational equipment. This assembly includes a stationary structure, a rotating structure rotatable about an axial centerline, and a non-contact seal assembly. The non-contact seal assembly is configured to substantially seal a gap between the stationary structure and the rotating structure. The non-contact seal assembly includes a seal shoe configured to sealingly engage the rotating structure axially along the axial centerline.

Abstract: Disclosed is a flutter damper, including an acoustic liner having a perforated radial inner face sheet and a radial outer back sheet, the acoustic liner being configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber secured to the radial outer back sheet, the chamber being in fluid communication with the acoustic liner, and the chamber being configured for peak acoustical energy absorption at a frequency range that is associated with one or more fan flutter modes, and at least one stiffening structure connected to a top surface of the chamber that tunes the top surface out of the frequency range associated with one or more fan flutter modes.

Abstract: Disclosed is flutter damper including a first cavity having a radially inner side in fluid communication with a flow path, and a second cavity having a radially inner side in fluid communication with a radially outer side of the first cavity, and the flutter damper having an impedance characteristic at one or more target frequencies defined as ftarget=fS,ND+?·ND wherein fS,ND is a resonance frequency corresponding to a structural mode of a rotating component, ND is a nodal diameter count of the structural mode, and ? is a rotational speed of the rotating component, and wherein the flutter damper has the following impedance characteristic at the one or more targeted frequencies R?2?c ?3?c?X??0.6?c wherein R is the real part of the impedance characteristic, X is the imaginary part of the impedance characteristic, ? is air density, and c is speed of sound.

Abstract: In one exemplary embodiment, an airfoil for a turbine engine includes an airfoil that has pressure and suction sides and extends in a radial direction from a 0% span position at an inner flow path location to a 100% span position at an airfoil tip. The airfoil has a curve that corresponds to a relationship between a leading edge dihedral and a span position. The leading edge dihedral has a portion of the curve with a change in dihedral in the range of 90% to 100% span position of greater than 10°. A positive dihedral corresponds to suction side-leaning. A negative dihedral corresponds to pressure side-leaning.

Abstract: Disclosed is a flutter damper, including an acoustic liner having a perforated radial inner face sheet and a radial outer back sheet, the acoustic liner being configured for peak acoustical energy absorption at a frequency range that is greater than a frequency range associated with fan flutter, a chamber secured to the radial outer back sheet, the chamber being in fluid communication with the acoustic liner, and the chamber being configured for peak acoustical energy absorption at a frequency range that is associated with one or more fan flutter modes, and at least one stiffening structure connected to a top surface of the chamber that tunes the top surface out of the frequency range associated with one or more fan flutter modes.

Abstract: Disclosed is flutter damper including a first cavity having a radially inner side in fluid communication with a flow path, and a second cavity having a radially inner side in fluid communication with a radially outer side of the first cavity, and the flutter damper having an impedance characteristic at one or more target frequencies defined as ftarget=fS,ND+?·ND wherein fS,ND is a resonance frequency corresponding to a structural mode of a rotating component, ND is a nodal diameter count of the structural mode, and ? is a rotational speed of the rotating component, and wherein the flutter damper has the following impedance characteristic at the one or more targeted frequencies R?2?c ?3?c?X??0.6?c wherein R is the real part of the impedance characteristic, X is the imaginary part of the impedance characteristic, ? is air density, and c is speed of sound.

Abstract: In one exemplary embodiment, an airfoil for a turbine engine includes an airfoil that has pressure and suction sides and extends in a radial direction from a 0% span position at an inner flow path location to a 100% span position at an airfoil tip. The airfoil has a curve that corresponds to a relationship between a leading edge dihedral and a span position. The leading edge dihedral has a portion of the curve with a change in dihedral in the range of 90% to 100% span position of greater than 10°. A positive dihedral corresponds to suction side-leaning. A negative dihedral corresponds to pressure side-leaning.