Control of internal flow separation using synthetic jet actuators

2000 ◽  
Author(s):  
M. Amitay ◽  
D. Parekh ◽  
D. Pitt ◽  
V. Kibens ◽  
A. Glezer
Keyword(s):  
Flow Separation ◽  
Internal Flow ◽  
Synthetic Jet ◽  
Synthetic Jet Actuators ◽  
Jet Actuators

A New Class of Synthetic Jet Actuators—Part I: Design, Fabrication and Bench Top Characterization

2005 ◽  
Vol 127 (2) ◽  
pp. 367-376 ◽  
Author(s):  
J. L. Gilarranz ◽  
L. W. Traub ◽  
O. K. Rediniotis
Keyword(s):  
Flow Separation ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Flow Separation Control ◽  
Synthetic Jet Actuators ◽  
New Class ◽  
Momentum Coefficient ◽  
Jet Actuators ◽  
In Series ◽  
Exit Slot

Although the potential of synthetic jets as flow separation control actuators has been demonstrated in the existing literature, there is a large gap between the synthetic jet actuators (SJA) used in laboratory demonstrations and the SJAs needed in realistic, full-scale applications, in terms of compactness, weight, efficiency, control authority and power density. In most cases, the SJAs used in demonstrations are either too large or too weak for realistic applications. In this work, we present the development of a new class of high-power synthetic jet actuators for realistic flow control applications. The operating principle of the actuator is the same as that of crankshaft driven piston engines, which makes a significant part of the technology necessary for the actuator development available off-the-shelf. The design of the actuator is modular and scalable. Several “building block” units can be stacked in series to create the actuator of the desired size. Moreover, active exit slot reconfiguration, in the form of variable exit slot width, decouples the actuator frequency from the actuator jet momentum coefficient and allows the user to set the two independently (within limits). Part I of this paper presents the design, fabrication and bench top characterization of the actuator. Several versions of the actuator were designed, built and tested, leading up to the development of a six-piston compact actuator that has a maximum power consumption of 1200 W (1.6 hp) and can produce (for the tested conditions) peak exit velocities as high as 124 m/s. In Part II, the actuator was housed in the interior of a NACA0015 profiled wing with a chord of 0.375 m (14.75 inches). The assembly’s performance in controlling flow separation was studied in the wind tunnel.

Control of Flow Separation and Its Associated Physics on a NACA0015 Using Synthetic Jet Actuators

2006 ◽  
Author(s):  
Wei Long Siauw ◽  
Jean Tensi ◽  
Se´bastien Bourgois ◽  
Jean-Paul Bonnet ◽  
Jean-Marc Breux ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Flow Separation ◽  
Laser Light ◽  
Laser Sheet ◽  
Synthetic Jet ◽  
Chord Length ◽  
Flow Physics ◽  
Synthetic Jet Actuators ◽  
Jet Actuators

Wind tunnel flow control experiments are conducted on two NACA0015 airfoil models, one of which having a chord length of 1.0m and the other having a chord of 0.35m, with the aim of exploring the separated flow physics and delaying flow separation. The larger model is tested in a low speed wind tunnel, measuring 1.25m by 1.25m at a Reynolds number of 0.4 and 0.27 million. This model is used to provide a quick proof of concept concerning the efficiency of various synthetic jet designs. Laser light visualization and Particle Image Velocimetry (PIV) studies are performed on this model. The synthetic jet actuators implemented (mechanically and acoustically generated) is realized through holes (2 and 3mm in diameter). The actuators are positioned at 20% or 70% of chord length from the leading edge for controlling separation at incidences between 12° and 15°. Flow separation delay and reattachment, depending on the frequency and momentum of the synthetic jet are observed qualitatively via laser sheet visualization in all cases. The efficiency of the actuator is quantified via the extent of separation observed with the PIV measurements. The technique of Proper Orthogonal Decomposition (POD) is applied to further reveal the large eddies in the separated shear layer and its interaction with the boundary layer. The smaller model is tested in a larger wind tunnel measuring 2.4m by 2.6m at a Reynolds number of 0.9 million. This is a more realistic flow condition with minimal wall and aspect ratio influence as compared to the larger model. The main experimental objective concerning this model is to quantify the baseline aerodynamic of the NACA0015 before implementation of synthetic jets. Laser light and surface oil visualizations are performed. Measurements concerning surface pressure and wake velocity characteristics are also made for this model. The lift of which is estimated via the integration of surface static pressure and the drag is estimated by wake survey technique using a pitot tube that is made to traverse in the wake. In addition, time resolved data are obtained in the wake of the airfoil by means of hotwires. Both hotwire measurement reveal typical Strouhal number of 0.34–0.4. These results are extrapolated to the large airfoil for interpretation of the flow physics during control. To sum up, the main results in the current study highlight the characteristics of the baseline airfoil and the ability of synthetic jet actuator techniques to obtain significant delay of the separation.

Towards the Design of Synthetic-jet Actuators for Full-scale Flight Conditions

2007 ◽  
Vol 78 (3-4) ◽  
pp. 283-307 ◽  
Author(s):  
Shan Zhong ◽  
Mark Jabbal ◽  
Hui Tang ◽  
Luis Garcillan ◽  
Fushui Guo ◽  
...  
Keyword(s):  
Synthetic Jet ◽  
Full Scale ◽  
Synthetic Jet Actuators ◽  
Jet Actuators
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