摘要:
The present invention provides flow field control techniques that adapt the aft body region flow field to eliminate or mitigate the development of massive separated flow field zones and associated unsteady vortical flow field structures. Embodiments of the present invention use one or more distributed arrays of flow control devices (submerged in the boundary layer) to create disturbances in the flow field that inhibit the growth of larger vortical structures and/or to energize the aft body shear layer to keep the shear layer attached the aft body surface. These undesirable aerodynamic phenomena produce increased vehicle drag which harms vehicle range, persistence, and loiter capabilities. Additionally, the unsteady nature of the turbulent vortical structures shed in the aft body wake region may produce increased dynamic buffeting and aft body heating by entraining nozzle jet exhaust (a.k.a. jet wash) —requiring additional structural support, shielding, and vehicle weight.
摘要:
In one embodiment, a wing includes a low pressure side, a high pressure side opposite the low pressure side, and a drag reducing apparatus coupled to the low pressure using an adhesive. The drag reducing apparatus includes a first side coupled to the low pressure side of the wing, and a second side opposite the first side, the second side comprising a plurality of vortex generators arranged in an array configuration, the array configuration of vortex generators operable to weaken a wingtip vortex generated by the wing by generating one or more vane vortices near an end of the low pressure side of the wing.
摘要:
An airfoil tip vortex mitigation arrangement comprising one or more flow directors configured and positioned to re-direct freestream air over a low pressure surface of an airfoil in such a way as to displace and weaken a main tip vortex generated at a tip of the airfoil.
摘要:
An apparatus for reducing heating effects of an exhaust plume of a jet engine on an impinged surface includes fluid injectors disposed adjacent and aimed into an exhaust plume zone that's to be occupied by an exhaust plume when the engine is running. A flow generator transmits fluid flow into such an exhaust plume through the injectors. Each injector emits fluid in at least two divergent directions to increase the cross-sectional area of the exhaust plume by forming fluidic lobes in the exhaust plume.
摘要:
A prismatic vortex generator for attenuating flow separation which occurs during supersonic flow of air over structure such as an aircraft airfoil, its fuselage, surfaces forming a part of a jet engine inlet, or similar surfaces subjected to supersonic airflow. A series of prismatic vortex generators are provided, each of which is configured to generate a vortex which attenuates flow separation and weight drag resulting from the supersonic airflow. Each prismatic vortex generator has a prismatic shape with a base, leading and trailing ends, and sidewalls that incline toward and join each other to form an apex. The leading end of each prismatic vortex generators is inclined away from the direction of flow.
摘要:
A non-invasive system, method, and apparatus for control input prediction and state verification of an aircraft's fluidic vectoring exhaust is disclosed. The control system derives a desired vector state, then predicts and sets the fluidic injection input required to produce the desired vector state. A vectored state verification routine is used to determine the resulting vector state for feedback to the control system.
摘要:
The present invention reveals a method and apparatus for more efficiently injecting a primary fluid flow in a fluid ejector used to pump lower velocity fluid from a secondary source. In one embodiment, the primary fluid flow is a pulsed or unsteady fluid flow contained within an inner nozzle situated within a secondary flow field. This secondary fluid flow is bounded within the walls of an ejector or shroud. The secondary and primary fluid flows meet within the ejector shroud section wherein the secondary fluid flow is entrained by the primary fluid flow. The geometry of the ejector shroud section where the primary and secondary fluids mix is such as to allow the beginning of primary injector pulse to be synchronized with an acoustic wave moving upstream through the ejector initiated by the exiting of the previous pulse from the ejector shroud. The ejector's geometric properties are determined by the acoustic properties, frequency, duty cycle, and amplitude, of the pulsed primary fluid flow. Furthermore, the frequency, duty cycle and amplitude of the primary fluid flow may be varied in order to vary the efficiency of the injector.
摘要:
An airfoil tip vortex mitigation arrangement comprising one or more flow directors configured and positioned to re-direct freestream air over a low pressure surface of an airfoil in such a way as to displace and weaken a main tip vortex generated at a tip of the airfoil.
摘要:
An exhaust impingement cooling device for reducing heating effects of an exhaust plume on an impinged surface. An exhaust nozzle exit screen is positioned across an exhaust plume flow path, and includes a plurality of flowpath diverging apertures that spread at least a portion of an exhaust plume that is being emitted along the exhaust plume flow path from an exhaust plume source. Flow control jets are arrayed within the exhaust plume flow path in respective positions where their operation will augment the flow of exhaust plume gases through the screen, thereby increasing the momentum and mixing of the exhaust plume with cooler ambient air.
摘要:
A pulsed-jet active flowfield control actuation system enhances the rate of heat transfer and heat removal in a heat exchanger for better management of thermal loads. The pulsed jet actuators impart an unsteady component of velocity to the working fluid of the heat exchanger. This design increases the convective heat transfer, and avoids increases in heat exchanger volume and weight for a given performance value.