Experimental Study on the Use of Synthetic Jet Actuators for Lift Control

2016 ◽  
Author(s):  
Ricardo B. Torres ◽  
Gustaaf B. Jacobs ◽  
Michael J. Cave
Keyword(s):  
Experimental Study ◽  
Reynolds Number ◽  
Shear Layer ◽  
Synthetic Jet ◽  
Inlet Guide Vane ◽  
Trailing Edge ◽  
Synthetic Jet Actuator ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Lift Control

An experimental study on the use of synthetic jet actuators for lift control on a generic compressor airfoil is conducted. A wind tunnel model of a NACA 65(2)-415 airfoil, representative of the cross section of an Inlet Guide Vane (IGV) in an industrial gas compressor, is 3D-printed. Nine synthetic jet actuators are integrated within a planar wing section with their slots covering 61% of pressure side of the airfoil span, located 13% chord upstream of the trailing edge. The Helmholtz frequency of the slot is matched closely with the piezoelectric element material frequency. The slot is designed so that the bi-morph actuation creates a jet normal to the airfoil surface. By redirecting or vectoring the shear layer at the trailing edge, the synthetic jet actuator increases lift and decreases drag on the airfoil without a mechanical device or flap. Tests are performed at multiple Reynolds number ranging from Re=150,000 to Re=450,000. The increased lift of the integrated synthetic jet actuator is dependent on the Reynolds number and free stream velocity, the actuation frequency, and angle of attack. For actuation at 1450 Hz the synthetic jet actuator increases lift up to 7%. The synthetic jet increases L/D up to 15%. Velocity contours obtained through PIV show that the synthetic jet turns the trailing edge shear layer similar to a Gurney flap.

Numerical Evaluation of the Effectiveness of Micro Pulsating Water Jets for Cooling of Microchips

2009 ◽  
Author(s):  
F. L. Hew ◽  
V. Timchenko ◽  
J. A. Reizes ◽  
E. Leonardi
Keyword(s):  
Heat Transfer ◽  
Minimum Temperature ◽  
Impinging Jets ◽  
Synthetic Jet ◽  
Maximum Temperature ◽  
Distinct Advantage ◽  
Synthetic Jet Actuator ◽  
Synthetic Jet Actuators ◽  
Micro Channels ◽  
Jet Actuators

In this study the effects of having multiple synthetic jet actuators and multiple orifices in a single jet actuator on creating better flow mixing and improving heat transfer in micro-channels have been investigated numerically. Unsteady computations of laminar flow have been performed for two dimensional configurations of micro-channel open at either end. A constant heat flux of 1 MWm−2 at the top of the silicon wafer represented the heat generated by the microchip. Synthetic jet actuators were attached to the bottom wall of the channel, with the 50 μm wide orifice. It is shown that by using double orifices single synthetic jet actuator, the heat transfer enhancement in micro-channels can be greatly improved. At the end of 30 cycles of actuation, the maximum temperature in the wafer has been reduced by approximately 27 K and the minimum temperature on the bottom of the wafer has been reduced by approximately 19 K in comparison with the steady flow values. In comparison with a single orifice synthetic jet actuator, double orifices synthetic jet actuator led to an additional 10 K reduction of the maximum temperature in wafer and 4 K reduction of minimum temperature on the interface of the wafer and water. It was demonstrated that the number of synthetic jet actuators is not the main factor influencing the thermal performance. The crucial factor is the number of impinging jets generated from the orifice which encourages better mixing in the flow. However, there is a distinct advantage associated with having multiple jet actuators in that out of phase flow could be generated which led to even lower temperatures than the in-phase jets.

THE MECHANISM OF JET VECTORING USING SYNTHETIC JET ACTUATORS

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1619-1622 ◽  
Author(s):  
ZHEN-BING LUO ◽  
ZHI-XUN XIA
Keyword(s):  
Static Pressure ◽  
Deflection Angle ◽  
Control Mechanism ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Control Mechanisms ◽  
Synthetic Jet Actuator ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Main Factors

The control mechanism of jet vectoring using synthetic jet actuators is investigated. The final deflection angle of the primary jet is a result of the primary jet controlled by synthetic jets at three different regions. The lower static pressure near the primary jet exit induced by the synthetic jet, the entrainment and absorption of the primary jet fluid by the synthetic jet during the blowing and the suction stroke, the coupling and interaction between the vortices of synthetic jet and the shear layer of the primary jet are the main control mechanisms for the synthetic jet actuator vectoring a primary jet. The main factors influencing jet vectoring are analyzed and summarized, and a preparatory model for jet vectoring using synthetic jet actuator is presented.

Experimental Study of the Dynamics of Synthetic Jet Actuators With Different Orifice Sizes

2005 ◽  
Author(s):  
Rahul Sekhri ◽  
Marco P. Schoen ◽  
Feng Lin ◽  
Brian G. Williams
Keyword(s):  
Experimental Study ◽  
Sound Pressure ◽  
Closed Loop ◽  
Solid Wall ◽  
Mechanical Vibration ◽  
Synthetic Jet ◽  
Control Laws ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Active Flow

Synthetic jet actuators (SJA) are one of the newly developed actuators that have demonstrated its great potentials in active flow applications, particularly in closed-loop flow controls. The SJA contains a piezoelectric membrane in a cavity, which vibrates and generates a periodic jet at the exit of the cavity through an orifice that is mounted flush with the solid wall of the flow field. In order to design the feedback control laws, it is crucial to be able to quantitatively capture the dynamics of SJA. In this paper, the dynamics of SJAs with six different orifice sizes are experimentally investigated. A synthesis using system identification for the purpose of constructing mathematical models of these zero mass-flux actuators is offered. The experimental study includes two output parameters, the acoustic sound pressure generated by the SJA and the mechanical membrane vibration of the SJA. State-space models for these outputs (sound pressure and mechanical vibration) are developed as a function of orifice size. These results form a foundation for future intelligent design of SJA.

scholarly journals Synthetic jet actuator with two opposite diaphragms

2020 ◽  
Vol 24 (1) ◽  
pp. 17-25
Author(s):  
Emil Smyk ◽  
Sylwester Wawrzyniak ◽  
Kazimierz Peszyński
Keyword(s):  
Reynolds Number ◽  
Active Flow Control ◽  
Input Power ◽  
Synthetic Jet ◽  
Energetic Efficiency ◽  
Synthetic Jet Actuator ◽  
Jet Actuators ◽  
Device Use ◽  
Active Flow ◽  
Key Parameter

AbstractThe synthetic jet actuators are one of the most investigated types of actuators used in heat transfer and active flow control. The energetic efficiency of actuators is a key parameter determining the possibility of device use. The actuators with two or more diaphragms have higher efficiency than the actuators with only one. The paper presents the investigations of the acoustic synthetic jet actuator with two opposite diaphragms. In the paper, synthetic jet velocity, Reynolds number and the energetic efficiency as a function of oscillating actuator frequency, for a different cavity, orifice configuration and one real input power P0 = 2 W were studied. The possibility of theoretical calculation of first and second resonance frequency were checked. The coupling ratio for actuators was calculated. The maximum energetic efficiency was η = 8.67% and Reynolds number Re = 8503. The possibility of using the same dependencies and rules during the design of actuators with two opposite diaphragms as in the case of actuators with one diaphragm was demonstrated. The results may be useful in the design of the actuators of the two membranes.

The Application of Synthetic Jet Actuators for the Modification of the Characteristics of Separated Shear Layers

Volume 1 ◽  
2004 ◽  
Author(s):  
Mark Watson ◽  
Artur J. Jaworski ◽  
Norman J. Wood
Keyword(s):  
Surface Pressure ◽  
Leading Edge ◽  
Shear Layers ◽  
Synthetic Jet ◽  
Wing Surface ◽  
Trailing Edge ◽  
Spectral Content ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Swept Wings

This paper presents an experimental investigation related to controlling the unsteady characteristics of the separated shear layers occurring over highly swept wings, and in particular focuses on application of synthetic jet actuators for modification of unsteady dynamic loading on the wing surface due to the phenomenon referred to as vortex breakdown (burst). In the post burst flow region the surface pressure measurements reveal the presence of certain characteristic spectral peaks that are thought to represent the presence of a spiralling filament of vorticity inside the expanded vortex that is known to be present in the burst flow over swept wings. This paper details an investigation into how the use of an array of 18 discrete synthetic jet actuators, distributed along the leading edge of a delta wing with a 60° sweep angle, can be used to alter the spectral content of this unsteadiness and reduce the level of unsteady pressure found in the post-burst region toward the wing trailing edge by up to 40%. Measurements of the surface pressure spectral distributions over the wing are presented together with PIV measurements of the vortex cross-section, conducted in the successive planes parallel to the wing trailing edge. Additional surface flow visualisation indicates that the effect of the actuators on the leading edge boundary layer is to induce local separation delays close to each actuator orifice, which introduce “ripples” into the shear layer as it separates. The results obtained are used to formulate an interpretative hypothesis attempting to explain the mechanisms responsible for modification of the spectral content and the level of excitation measured on the wing surface.

Low Reynolds Number Flow Control Over an Airfoil Using Synthetic Jet Actuators

2010 ◽  
Author(s):  
Sebastian D. Goodfellow ◽  
Serhiy Yarusevych ◽  
Pierre Sullivan
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Flow Visualization ◽  
Low Reynolds Number ◽  
Excitation Frequency ◽  
Synthetic Jet ◽  
Hot Wire ◽  
Synthetic Jet Actuators ◽  
Jet Actuators ◽  
Low Reynolds

The influence of periodic excitation from synthetic jet actuators, SJA, on boundary layer separation and reattachment over a NACA 0025 airfoil at a low Reynolds number is studied. All experiments were performed in a low-turbulence recirculating wind tunnel at a Reynolds number of 100000 and angle of attack of α = 0°. Mounted just below the surface of the airfoil, the SJA consists of four (32.77mm diameter) piezo-electric ceramic diaphragms positioned in a single row. Flow visualization and hot wire tests were conducted with the SJA outside of the airfoil to characterize the exit flow. Results from flow visualization show a vertical jet pulse accompanied by two counter rotating vortices being produced at the exit of the simulated slot, with the vortices shed at the excitation frequency. Based on flow visualization results, the length scales of successive vortices were used to estimate the exit velocities. Hot-wire measurements determined the maximum jet velocity for a range of excitation frequencies (f = 50Hz–2.7kHz) and voltages (Vp–p = 50V–300V), which was used to characterize the excitation amplitude in terms of the momentum coefficient (cμ). With the SJA installed in the airfoil, preliminary flow visualization results show a reattachment of the boundary layer and a significant reduction in wake width.

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