A panel for an active laminar flow control arrangement may comprise a longitudinal wall and one or more division walls extending from the longitudinal wall and extending between the first end and the second end. The panel may be coupled to a nacelle outer skin via a plurality of adhesive fasteners pre-installed onto an inner surface of the outer skin and onto stiffeners and/or stringers associated with the outer skin.

Fluid systems are described herein. An example embodiment of a fluid system has a first body portion, a second body portion, a plurality of supports, a plurality of fluid pressurizers, and a plurality of ducts. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. Each duct of the plurality of ducts is disposed within the channel cooperatively defined by the first body portion and the second body portion.

A reaction-jet helicopter having an air compressor and a power source operable to power the compressor. The air compressor is in fluid communication with a cavity in a rotor blade of the reaction-jet helicopter. The rotor blade has one or more openings for the expulsion of compressed air from the cavity thereby resulting in rotation of the rotor blade. The reaction jet helicopter further has an arrangement for manipulating airflow between the compressor and the one or more openings. This results in reduced losses of energy as the airflow travels from the compressor to the one or more openings.

An airfoil for flow control is disclosed having an outer skin in contact with an ambient air flow, wherein the outer skin extends between a leading edge and a trailing edge with two opposite lateral sides, and surrounds an interior space. The outer skin comprises a porous section in the area of the leading edge, a pressure chamber arranged in the interior space and fluidly connected to the porous section, an air inlet fluidly connected to the pressure chamber, and an air outlet fluidly connected to the pressure chamber.

An airfoil for flow control is disclosed having an outer skin in contact with an ambient air flow, wherein the outer skin extends between a leading edge and a trailing edge with two opposite lateral sides, and surrounds an interior space. The outer skin comprises a porous section in the area of the leading edge, a pressure chamber arranged in the interior space and fluidly connected to the porous section, an air inlet fluidly connected to the pressure chamber, and an air outlet fluidly connected to the pressure chamber.

Drag modification systems for aircraft and related methods. An example system for modifying drag on an aircraft includes a boundary layer intake plenum and an eductor. The eductor defines a primary inlet to receive a primary fluid, a secondary inlet in fluid communication with the intake plenum to receive a secondary fluid entrained from the intake plenum, and an outlet to exhaust a mixed flow including the primary fluid and the secondary fluid. The primary fluid is a motive fluid having flow parameters to generate a suction at the secondary inlet.

A hybrid wing aircraft has an engine embedded into a body of the hybrid wing aircraft. The embedded engine has a fan that is received within a nacelle. The body of the aircraft provides a boundary layer over a circumferential portion of a fan. A system delivers additional air to correct fan stability issues raised by the boundary layer.

Systems and methods are described herein to implement transverse momentum injection at low frequencies to directly modify large-scale eddies in a turbulent boundary layer on a surface of an object. A set of transverse momentum injection actuators may be positioned on the surface of the object to affect large-scale eddies in the turbulent boundary layer. The system may include a controller to selectively actuate the transverse momentum injection actuators with an actuation pattern to affect the large-scale eddies to modify the drag of the fluid flow on the surface. In various embodiments, the transverse momentum injection actuators may be operated at frequencies less than 10,000 Hertz.

Variable-porosity panel systems and associated methods. A variable-porosity panel system includes a panel assembly with an exterior layer defining a plurality of exterior layer pores and a sliding layer adjacent to the exterior layer and defining a plurality of sliding layer pores. The variable-porosity panel system additionally includes a shape memory alloy (SMA) actuator configured to translate the sliding layer relative to the exterior layer to modulate a porosity of the panel assembly. The SMA actuator includes an SMA element configured to exert an actuation force on the sliding layer and at least partially received within an SMA element receiver of the sliding layer. The SMA element extends out of the sliding layer only at a sliding layer first end. A method of operating the variable-porosity panel system includes assembling the variable-porosity panel system and/or transitioning the panel assembly of the variable-porosity panel system among the plurality of panel configurations.

Fluid systems are described herein. An example embodiment of a fluid system has a first body portion, a second body portion, a plurality of supports, a plurality of fluid pressurizers, and a plurality of ducts. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. Each duct of the plurality of ducts is disposed within the channel cooperatively defined by the first body portion and the second body portion.