Abstract: Methods, systems, and computer-readable media for controlling a toolface of a downhole tool are described. The toolface of the downhole tool, and a toolface setpoint, are determined. Based on the toolface and the toolface setpoint, a toolface error is determined. Based on the toolface error, one or more drilling parameter setpoints are selected from among multiple drilling parameter setpoints. The selected one or more drilling parameter setpoints are adjusted. The adjusted one or more drilling parameter setpoints are inputted to one or more drilling controllers for controlling the toolface of the downhole tool.

Abstract: Methods, systems, and computer-readable media for controlling a toolface of a downhole tool are described. The toolface of the downhole tool, and a toolface setpoint, are determined. Based on the toolface and the toolface setpoint, a toolface error is determined. Based on the toolface error, one or more drilling parameter setpoints are selected from among multiple drilling parameter setpoints. The selected one or more drilling parameter setpoints are adjusted. The adjusted one or more drilling parameter setpoints are inputted to one or more drilling controllers for controlling the toolface of the downhole tool.

Abstract: There is described a method of determining a reactive torque factor for use in controlling a toolface of a downhole tool. For each of one or more sliding operations, a change in a top drive position of a drive unit operable to rotate a drill string connected to the downhole tool is determined, a change in a toolface of the downhole tool is determined, and a change in a differential pressure is determined. Based on the change in the top drive position, the change in the toolface, and the change in the differential pressure, a reactive torque factor is determined.

Abstract: Methods, systems, and computer-readable media for controlling a toolface of a downhole tool are described. The toolface of the downhole tool, and a toolface setpoint, are determined. Based on the toolface and the toolface setpoint, a toolface error is determined. Based on the toolface error, one or more drilling parameter setpoints are selected from among multiple drilling parameter setpoints. The selected one or more drilling parameter setpoints are adjusted. The adjusted one or more drilling parameter setpoints are inputted to one or more drilling controllers for controlling the toolface of the downhole tool.

Abstract: Methods, systems, and computer-readable media for controlling a toolface of a downhole tool are described. The toolface of the downhole tool, and a toolface setpoint, are determined. Based on the toolface and the toolface setpoint, a toolface error is determined. Based on the toolface error, one or more drilling parameter setpoints are selected from among multiple drilling parameter setpoints. The selected one or more drilling parameter setpoints are adjusted. The adjusted one or more drilling parameter setpoints are inputted to one or more drilling controllers for controlling the toolface of the downhole tool.

Abstract: There is described a method of determining a reactive torque factor for use in controlling a toolface of a downhole tool. For each of one or more sliding operations, a change in a top drive position of a drive unit operable to rotate a drill string connected to the downhole tool is determined, a change in a toolface of the downhole tool is determined, and a change in a differential pressure is determined. Based on the change in the top drive position, the change in the toolface, and the change in the differential pressure, a reactive torque factor is determined.

Abstract: Methods, systems, and computer-readable media for controlling a toolface of a downhole tool are described. The toolface of the downhole tool, and a toolface setpoint, are determined. Based on the toolface and the toolface setpoint, a toolface error is determined. Based on the toolface error, one or more drilling parameter setpoints are selected from among multiple drilling parameter setpoints. The selected one or more drilling parameter setpoints are adjusted. The adjusted one or more drilling parameter setpoints are inputted to one or more drilling controllers for controlling the toolface of the downhole tool.

Abstract: A component system of a gas turbine engine including: a first component having an outer surface; a second component having an outer surface, the second component and the first component being in a facing spaced relationship defining an air passageway therebetween; and a first recess located in at least one of the outer surface of the first component proximate the air passage and the outer surface of the first component proximate the air passage, wherein the first recess is located proximate a throat within the air passageway stretching between the first component and the second component.

Abstract: An inlet guide vane having varied trailing edge geometry is provided. The inlet guide vane may have an inner diameter edge opposite an outer diameter edge, and may comprise a leading edge part and a trailing edge part. The trailing edge part may comprise a trailing edge length defining a length between a forward edge and an aft edge. The trailing edge length may vary in length. The trailing edge part may be displaced from the leading edge part at a stagger angle. The stagger angle may vary in displacement.

Abstract: The Aeroelastic Model using the Principal Shapes of modes (AMPS) is a method used to predict flutter in gas turbine engines. Modern gas turbine engines often include rotors with flexible disks and/or significant blade geometry variations. The AMPS method accounts for the varying blade mode shapes associated with flexible disks as well as changing blade geometry, providing accurate flutter predictions for a large number of modes from a relatively small number of CFD (computational fluid dynamics) simulations. The AMPS method includes determining a smaller set of principal shapes that approximates a larger set of structural modes of interest. Using linear superposition, aerodynamic forces associated with the vibration of the principal shapes can be used to construct the full aerodynamic coupling matrix associated with the structural modes of interest. An eigenvalue equation is solved to determine a damping distribution associated with the structural modes of interest.

Abstract: The Aeroelastic Model using the Principal Shapes of modes (AMPS) is a method used to predict flutter in gas turbine engines. Modern gas turbine engines often include rotors with flexible disks and/or significant blade geometry variations. The AMPS method accounts for the varying blade mode shapes associated with flexible disks as well as changing blade geometry, providing accurate flutter predictions for a large number of modes from a relatively small number of CFD (computational fluid dynamics) simulations. The AMPS method includes determining a smaller set of principal shapes that approximates a larger set of structural modes of interest. Using linear superposition, aerodynamic forces associated with the vibration of the principal shapes can be used to construct the full aerodynamic coupling matrix associated with the structural modes of interest. An eigenvalue equation is solved to determine a damping distribution associated with the structural modes of interest.

Abstract: An inlet guide vane provides improved, smooth airflow and avoids separation of flow even at high incidence angles. The inlet guide vane includes a strut having opposite side surfaces that are continuously curved to provide a controlled velocity distribution at the trailing edge of the strut. The inlet guide vane further includes a flap having a leading edge aligned behind the trailing edge of the strut. Generally, the strut and the flap are designed together so that low momentum air in the gap between the strut and the flap will be energized and entrained in the boundary layer of the flap. The airflow from the gap will remain attached to the flap to improve the flow from the flap.