摘要:
Active systems and methods for controlling aircraft vortices are disclosed. An apparatus in accordance with one embodiment is directed to an aircraft system that includes an airfoil having first and second oppositely facing flow surfaces and a tip. The system can further include a vortex dissipation device carried by the airfoil, with the vortex dissipation device including an orifice positioned to direct a flow of fluid outwardly from the tip, an actuator operatively coupled to the fluid flow orifice and positioned to change a manner in which flow is directed outwardly from the tip, and a controller operatively coupled to the actuator to direct the operation of the actuator. The vortex dissipation device can be activated to accelerate the rate at which vortices (e.g., wing tip vortices) dissipate after they are generated, for example, by alternately pulsing flow inwardly and outwardly through the fluid flow orifice.
摘要:
An apparatus comprises a platform configured to move in a streamwise direction, an actuation unit associated with a control surface of the platform, a fluid source configured to supply an airflow to the actuation unit, and a control unit for moving an air jet across the control surface. The actuation unit is configured to form a traversing air jet pointing in the streamwise direction.
摘要:
Coanda Effect and lift produced along a surface of an airfoil are increased by ducting compressed fluid from the engine to the surface of the airfoil. An engine produces exhaust gases that are predominantly directed toward an aft end of the aircraft by a cowling or other structure as an exhaust plume. One or more internal ducts extend from the engine to the surface of the airfoil to thereby transmit a compressed fluid from the engine to the surface in order to suppress flow separation along the surface, thereby causing the engine exhaust flow to remain attached to the surface over a wider span. Such structures and techniques may find particular use in aircraft designed to exploit upper surface blowing (USB) techniques and structures for short takeoff and landing (STOL) performance.
摘要:
Aircraft exhaust systems and methods are disclosed. In one embodiment, an integrated propulsion assembly includes a wing assembly having an upper surface and a lower surface, and a propulsion unit at least partially disposed within the wing assembly. An exhaust system is configured to conduct an exhaust flow emanating from the propulsion unit to an exhaust aperture. The exhaust aperture is positioned proximate a trailing edge of the wing assembly, and has an aspect ratio of at least five. In further embodiments, the wing assembly includes a flap member moveably coupled along a trailing edge portion of the wing assembly, and the exhaust aperture is configured to direct the exhaust flow over at least a portion of the flap member.
摘要:
Integrated engine exhaust systems and methods for reducing drag and thermal loads are disclosed. In one embodiment, a propulsion system includes an engine installation configured to be mounted on a wing assembly of an aircraft. The engine installation includes an engine, and an exhaust system operatively coupled to the engine. The exhaust system includes at least one nozzle configured to exhaust an exhaust flow from the engine. The nozzle includes a variable portion configured to vary an exit aperture of the nozzle from a first shape to a second shape to change a flowfield shape of at least a portion of the nozzle flowfield proximate the wing assembly, thereby reducing at least one of drag and thermal loading on the wing assembly. In a further embodiment, the exhaust system includes an inner nozzle that exhausts a core exhaust flow, and an outer nozzle that exhausts a secondary exhaust flow, the outer nozzle having the variable portion configured to vary the exit aperture of the outer nozzle.
摘要:
A tamper indicating closure member for containers is disclosed having a cap member with a top wall and a peripheral skirt integral therewith. Also included is a separable band portion interconnected to the skirt by a frangible bridge element. The band portion is capable of coacting with an axially inclined ramp surface defined by a circumferential bead on the neck, thereby substantially preventing transverse movement of the closure band portion relative to the container neck.
摘要:
A propulsion system for an aircraft includes an airfoil, an engine having an engine cowling carried by the airfoil and configured to produce exhaust gases that are predominantly directed toward an aft end of the airfoil by the engine cowling as engine exhaust, a propulsion flap carried by the airfoil and disposed aft of the engine cowling and a plurality of exhaust ejection orifices provided in the propulsion flap and adapted to receive at least a portion of the exhaust gases from the engine cowling.
摘要:
Lift produced by an airfoil of an aircraft is increased by suppressing fluid detachment from the surface of the airfoil. An engine cowling extends outwardly from the surface of the airfoil that has an exit plane configured for directing exhaust gases toward a rear of the aircraft. Fences extending outwardly from the surface and proximate to the exit plane of the engine cowling are configured to guide the exhaust gases along at least a portion of the airfoil surface, thereby restricting spanwise movement of the gases and increasing the Coanda Effect exhibited by the gases, thereby increasing the amount of lift produced along the surface of the airfoil. Such techniques may be used in short take-off and landing (STOL) aircraft.
摘要:
A plastics container includes a neck and an outlet opening, a container body and a base; the base comprising a plurality of circumferentially spaced legs, each leg terminating in a foot portion on which the container is adapted to stand wherein each leg is provided with at least one longitudinally inwardly extending crease. Preferably each leg is provided with a single crease which extends downwardly and inwardly at least to the extent necessary so to substantially divide the foot portion of each leg into two separate support portions on which the container is adapted to stand.
摘要:
Active systems and methods for controlling aircraft vortices are disclosed. An apparatus in accordance with one embodiment is directed to an aircraft system that includes an airfoil having first and second oppositely facing flow surfaces and a tip. The system can further include a vortex dissipation device carried by the airfoil, with the vortex dissipation device including an orifice positioned to direct a flow of fluid outwardly from the tip, an actuator operatively coupled to the fluid flow orifice and positioned to change a manner in which flow is directed outwardly from the tip, and a controller operatively coupled to the actuator to direct the operation of the actuator. The vortex dissipation device can be activated to accelerate the rate at which vortices (e.g., wing tip vortices) dissipate after they are generated, for example, by alternately pulsing flow inwardly and outwardly through the fluid flow orifice.