Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: An aerodynamic surface assembly is provided to facilitate control of the flow over the aerodynamic surface. The aerodynamic surface assembly includes an aerodynamic surface defining an outer mold line over which a fluid is to flow in a downstream direction. The outer mold line defines a smooth contour that is interrupted by step down region that is inset relative to the smooth contour defined by the outer mold line upstream thereof. The aerodynamic surface defines an orifice opening in to the step down region. The aerodynamic surface assembly may also include an overhang extending from the outer mold line of the aerodynamic surface upstream at the orifice. The overhang extends in the downstream direction and at least partially over the orifice. The aerodynamic surface assembly may also include a fluidic actuator defining a pair of curved passageways extending from an input region and are in fluid communication with the orifice.

Abstract: A thermal energy harvesting system employs a hot flow conduit and a cold flow conduit with a flow routing device interruptibly interconnecting the hot flow conduit and cold flow conduit with a flow casing. At least one shape memory actuator (SMA) tube is in fluid contact with the flow casing and fixed at a first end. The flow routing device sequentially supplies hot flow from the hot flow conduit and cold flow from the cold flow conduit inducing rotation of the at least one SMA tube at a second end. A generator or alternator is operably connected to the second end of the at least one SMA tube.

Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: Piezoelectric actuators for synthetic jets and other devices are disclosed having orthotropic piezoelectric bimorphs with increased out-of-plane displacements for greater responsiveness to applied electric fields. In some embodiments, the piezoelectric actuators may include interdigitated electrodes applied to a surface of a piezoelectric plate to produce greater in-plane strains in the plate and greater out-of-plane displacements of a flexible diaphragm of the synthetic jet. In other embodiments, the actuator includes an orthotropic piezoceramic plate having a greater d coupling coefficient in one in-plane direction and in the other in-plane direction to cause desired diaphragm out-of-plane displacements when an electric field is applied by electrodes.

Abstract: A thermal energy harvesting system employs a hot flow conduit and a cold flow conduit with a flow routing device interruptibly interconnecting the hot flow conduit and cold flow conduit with a flow casing. At least one shape memory actuator (SMA) tube is in fluid contact with the flow casing and fixed at a first end. The flow routing device sequentially supplies hot flow from the hot flow conduit and cold flow from the cold flow conduit inducing rotation of the at least one SMA tube at a second end. A generator or alternator is operably connected to the second end of the at least one SMA tube.

Abstract: A synthetic jet actuator and a method for optimizing a synthetic jet actuator to meet operating requirements and physical constraints may include estimating dimension and a resonance frequency of an air cavity of the synthetic jet actuator, and using the estimated resonance frequency to the estimate dimensions of a piezoelectric actuator of the synthetic jet actuator. Individual simulations of the air cavity and piezoelectric actuator, and a coupled simulation may be performed using the estimated dimensions, and the dimensions may be revised and simulations re-executed to match the resonance frequencies of the air chamber and the piezoelectric actuator. The method maybe yield a synthetic jet actuator having a resonance frequency of the piezoelectric actuator that is approximately equal to a quarter-wavelength resonance frequency of the air cavity.

Abstract: An aerodynamic surface assembly is provided to facilitate control of the flow over the aerodynamic surface. The aerodynamic surface assembly includes an aerodynamic surface defining an outer mold line over which a fluid is to flow in a downstream direction. The outer mold line defines a smooth contour that is interrupted by step down region that is inset relative to the smooth contour defined by the outer mold line upstream thereof. The aerodynamic surface defines an orifice opening in to the step down region. The aerodynamic surface assembly may also include an overhang extending from the outer mold line of the aerodynamic surface upstream at the orifice. The overhang extends in the downstream direction and at least partially over the orifice. The aerodynamic surface assembly may also include a fluidic actuator defining a pair of curved passageways extending from an input region and are in fluid communication with the orifice.

Abstract: A device for generating a synthetic jet is described. The device can include a flap, an actuator coupled to the flap and a chamber including an aperture. The flap forms a portion of the chamber. The flap is configured to oscillate in a flapping motion such that fluid is alternately drawn into the chamber via the aperture and expelled from the chamber via the aperture to form the synthetic jet. In some embodiments, multiple flaps can be used on a device to generate the synthetic jet.

Abstract: Systems and methods described herein provide for the control of airflow over a vertical control surface of an aircraft to enhance the forces produced by the surface. According to one aspect of the disclosure provided herein, the vertical control surface of the aircraft is engaged by active flow control actuators that interact with the ambient airflow to alter one or more characteristics of the airflow. An actuator control system detects a flow control event, and in response, activates the active flow control actuators to alter the airflow. According to various aspects, the flow control event is associated with a separation of the airflow, which is corrected through the activation of the appropriate active flow control actuators, increasing the forces produced by the vertical control surface of the aircraft.

Abstract: Apparatus and methods provide for a flow control actuator having a fluid cavity that is shaped to create periodic waveforms within the resulting resonant actuating flow with predetermined characteristics for actuating a high-speed fluid flow. According to various embodiments, a flow control actuator includes a power source for exciting the actuator fluid at a resonant frequency and a cavity shaped according to resonant macrosonic synthesis principles to maximize the exit velocity of the actuating flow at an orifice of the actuator.

Abstract: A device for generating a synthetic jet is described. The device can include a flap, an actuator coupled to the flap and a chamber including an aperture. The flap forms a portion of the chamber. The flap is configured to oscillate in a flapping motion such that fluid is alternately drawn into the chamber via the aperture and expelled from the chamber via the aperture to form the synthetic jet. In some embodiments, multiple flaps can be used on a device to generate the synthetic jet.

Abstract: Systems and methods described herein provide for the control of airflow over a vertical control surface of an aircraft to enhance the forces produced by the surface. According to one aspect of the disclosure provided herein, the vertical control surface of the aircraft is engaged by active flow control actuators that interact with the ambient airflow to alter one or more characteristics of the airflow. An actuator control system detects a flow control event, and in response, activates the active flow control actuators to alter the airflow. According to various aspects, the flow control event is associated with a separation of the airflow, which is corrected through the activation of the appropriate active flow control actuators, increasing the forces produced by the vertical control surface of the aircraft.

Abstract: Apparatus and methods provide for a flow control actuator having a fluid cavity that is shaped to create periodic waveforms within the resulting resonant actuating flow with predetermined characteristics for actuating a high-speed fluid flow. According to various embodiments, a flow control actuator includes a power source for exciting the actuator fluid at a resonant frequency and a cavity shaped according to resonant macrosonic synthesis principles to maximize the exit velocity of the actuating flow at an orifice of the actuator.