Wing tip vortex control using synthetic jets

2006 ◽  
Vol 110 (1112) ◽  
pp. 673-681 ◽  
Author(s):  
P. Margaris ◽  
I. Gursul
Keyword(s):  
Synthetic Jet ◽  
Synthetic Jets ◽  
Tip Vortex ◽  
Particle Image Velocimetry System ◽  
Driving Frequency ◽  
Velocity Measurements ◽  
Vortex Control ◽  
Image Velocimetry ◽  
Wing Tip ◽  
Jet Blowing

AbstractAn experimental investigation was conducted to study the effect of synthetic jet (oscillatory, zero net mass flow jet) blowing near the wing tip, as a means of diffusing the trailing vortex. Velocity measurements were taken, using a Particle Image Velocimetry system, around the tip and in the near wake of a rectangular wing, which was equipped with several blowing slots. The effect of the synthetic jet was compared to that of a continuous jet blowing from the same configurations. The results show that the use of synthetic jet blowing is generally beneficial in diffusing the trailing vortex and comparable to the use of continuous jet. The effect was more pronounced for the highest blowing coefficient used. The driving frequency of the jet did not generally prove to be a significant parameter. Finally, the instantaneous and the phase-locked velocity measurements helped explain the different mechanisms employed by the continuous and synthetic jets in diffusing the trailing vortex.

Examination of a Variable-Diameter Synthetic Jet

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Spencer O. Albright ◽  
Stephen A. Solovitz
Keyword(s):  
Particle Image Velocimetry ◽  
Vortex Ring ◽  
Mass Flux ◽  
Particle Image ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Variable Diameter ◽  
Constant Diameter ◽  
Image Velocimetry ◽  
Jet Actuators

Synthetic jet actuators are used to produce net axial momentum flow without net mass flux. Through strategic application, such devices can be used for flow control, propulsive thrust, and cooling. A novel application uses a variable-diameter orifice to constrict the exiting flow, and the motion can be synchronized with the pulse of the jet. This device is examined using phase-locked particle image velocimetry (PIV), permitting investigation of the flow fields and momentum flow. When compared to fixed-diameter synthetic jets, the variable-diameter actuator produces a larger vortex ring that lingers nearer the aperture. In addition, the experiments show increased momentum when the aperture is contracted in phase with the pulsing jet, with peak levels more than twice that of a constant-diameter jet.

Heat Transfer Measurements of Impinging Synthetic Air Jet

2007 ◽  
Author(s):  
Alan McGuinn ◽  
Tadhg S. O’Donovan ◽  
Darina B. Murray
Keyword(s):  
Heat Transfer ◽  
Flow Characteristics ◽  
Impinging Jets ◽  
Copper Plate ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Driving Frequency ◽  
Promising Alternative ◽  
Air Jet ◽  
Cooling Effects

The implementation of synthetic jets for use in the cooling of electronics is a relatively new technology. It is well established that effective rates of cooling can be achieved using conventional steady flow impinging jets. However it has been shown that synthetic jets can deliver similar cooling effects without the need for an air supply system and therefore represent an extremely promising alternative for thermal management applications. A study has been undertaken of the heat transfer distribution to an impinging synthetic jet flow. The jet is directed at a heated copper plate, which approximates a uniform wall temperature. Nusselt number profiles generated by the synthetic jet for various Reynolds numbers and heights above the plate were obtained. Time varying velocity measurements were also carried out to provide information about the flow characteristics of the synthetic jet and to aid with evaluation of the heat transfer data. For continuous jets mean heat transfer distributions have been shown to have a direct relation to jet velocity profiles, however, for synthetic jets fluctuations in local heat flux illustrate a significant dependence on the driving frequency.

Meso Scale Pulsating Jets for Electronics Cooling

2005 ◽  
Vol 127 (4) ◽  
pp. 503-511 ◽  
Author(s):  
Jivtesh Garg ◽  
Mehmet Arik ◽  
Stanton Weaver ◽  
Todd Wetzel ◽  
Seyed Saddoughi
Keyword(s):  
Heat Transfer ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Coefficient Of Performance ◽  
Small Scale ◽  
Driving Voltage ◽  
Driving Frequency ◽  
Air Velocity ◽  
Maximum Heat ◽  
Meso Scale

Microfluid devices are conventionally used for boundary layer control in many aerospace applications. Synthetic jets are intense small-scale turbulent jets formed from periodic entrainment and expulsion of the fluid in which they are embedded. The jets can be made to impinge upon electronic components thereby providing forced convection impingement cooling. The small size of these devices accompanied by the high exit air velocity provides an exciting opportunity to significantly reduce the size of thermal management hardware in electronics. A proprietary meso scale synthetic jet designed at GE Global Research is able to provide a maximum air velocity of 90m∕s from a 0.85 mm hydraulic diameter rectangular orifice. An experimental study for determining the cooling performance of synthetic jets was carried out by using a single jet to cool a thin foil heater. The heat transfer augmentation caused by the jets depends on several parameters, such as, driving frequency, driving voltage, jet axial distance, heater size, and heat flux. During the experiments, the operating frequency for the jets was varied between 3.4 and 5.4 kHz, while the driving voltage was varied between 50 and 90VRMS. Two different heater powers, corresponding to approximately 50 and 80 °C, were tested. A square heater with a surface area of 156mm2 was used to mimic the hot component and detailed temperature measurements were obtained with a microscopic infrared thermal imaging technique. A maximum heat transfer enhancement of approximately 10 times over natural convection was measured. The maximum measured coefficient of performance was approximately 3.25 due to the low power consumption of the synthetic jets.

Measurements of the velocity field of a wing-tip vortex, wandering in grid turbulence

2008 ◽  
Vol 601 ◽  
pp. 281-315 ◽  
Author(s):  
S. C. C. BAILEY ◽  
S. TAVOULARIS
Keyword(s):  
Free Stream ◽  
Tip Vortex ◽  
Grid Turbulence ◽  
Velocity Measurements ◽  
Free Stream Turbulence ◽  
Normal Probability ◽  
Rate Of Decay ◽  
Wing Tip Vortex ◽  
Point Velocity ◽  
Wing Tip

Velocity measurements were performed in a wing-tip vortex wandering in free-stream turbulence using two four-wire hot-wire probes. Vortex wandering was well represented by a bi-normal probability density with increasing free-stream turbulence resulting in increased amplitude of wandering. The most dominant wavelength of wandering was found to remain unaffected by free-stream conditions. Two-point velocity measurements were used to reconstruct the vortex velocity profile in a frame of reference wandering with the vortex. Increasing turbulence intensity was found to increase the rate of decay of the vortex peak circumferential velocity while the radial location of this peak velocity remained unchanged. These results are consistent with several possible vortex decay mechanisms, including the stripping of vorticity by azimuthally aligned vortical structures, transfer of angular momentum from the vortex to these structures during their formation and the deformation and breakup of the vortex by strong free-stream eddies.

PIV MEASUREMENTS OF DUAL SYNTHETIC JETS ACTUATOR DRIVEN BY ELECTRICAL FACTORS

2009 ◽  
Vol 23 (03) ◽  
pp. 417-420 ◽  
Author(s):  
ZHEN-BING LUO ◽  
ZHI-XUN XIA ◽  
BING LIU ◽  
DE-QUAN WANG ◽  
JIAN-XIN HU ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Driving Voltage ◽  
Transfer Phase ◽  
Piv Measurements ◽  
Synthetic Jet Actuator ◽  
Arbitrary Phase ◽  
Image Velocimetry

A dual synthetic jets actuator driven by different electrical factors was investigated using particle image velocimetry (PIV). A transfer-phase and sub-frequency technique was provided to capture the arbitrary phase of the dual synthetic jets, and a transfer-phase to equal technique was provided to determine the phase of the dual synthetic jets. The results show that both the amplitude and frequency of the electrical forcing voltages vastly affect the flow-field of the dual synthetic jets actuator. Both the forcing frequency and the driving voltage amplitudes contribute to the pressure difference and the area of the lower pressure, which determines the interactions of dual synthetic jets. The dual synthetic jet actuator exits a circumscription of electrical factors in which the actuator works efficiently.

Near wake development of a wing tip vortex under the effect of synthetic jet actuation

2016 ◽  
Vol 54 ◽  
pp. 88-107 ◽  
Author(s):  
Marouen Dghim ◽  
Mohsen Ferchichi ◽  
Ruben E. Perez ◽  
Maher BenChiekh
Keyword(s):  
Synthetic Jet ◽  
Tip Vortex ◽  
Near Wake ◽  
Wing Tip Vortex ◽  
Wing Tip

Wing tip vortex control by the pulsed MHD actuator

2016 ◽  
Author(s):  
I. A. Moralev ◽  
V. A. Biturin ◽  
P. N. Kazansky ◽  
M. Yu. Zaitsev ◽  
Vl. A. Kopiev
Keyword(s):  
Tip Vortex ◽  
Vortex Control ◽  
Wing Tip Vortex ◽  
Wing Tip

Investigating the Effects of Using Synthetic Jet on Wing Tip Vortex at Low Reynolds Number

2017 ◽  
Author(s):  
Djavad Kamari ◽  
Mehran Tadjfar
Keyword(s):  
Reynolds Number ◽  
Vortex Core ◽  
Synthetic Jet ◽  
Tip Vortex ◽  
Detached Eddy Simulation ◽  
Wing Model ◽  
Velocity Magnitude ◽  
Study Results ◽  
Wing Tip Vortex ◽  
Wing Tip

Evolution of wing tip vortex has been widely studied by many researchers. Winglet, jet, and suction devices have been implemented close to the wing tip to passively or actively mitigate the tip vortex effects. This study aims to investigate the effects of employing a synthetic jet at the tip of a half wing model. The flow was assumed to be incompressible, low speed and the Reynolds number based on chord length with aspect ratio equal to two for half wing was 1.8 × 105. Different reduced frequencies and momentum coefficients were applied. A Detached Eddy Simulation by considering Spalart-Allmaras as the turbulence model for subgrid scale zone and near the walls was employed to simulate the flow field study. Results showed large diffusivity in vortex core. Also, a reduction in longitudinal and total velocity magnitude has observed at vortex core region in the near wake.

Sign in / Sign up

Export Citation Format

Share Document