Performance Of Synthetic Jet Actuator Research Articles

Multiphysics Modeling of a Synthetic Jet Actuator in Operation

Active flow control is a promising technology for reducing noise, emissions, and power consumption in various applications. To better understand the performance of synthetic jet actuators, a computational model that couples structural mechanics with electrostatics, pressure acoustics, and fluid dynamics is needed. The model presented here was validated against experimental data and then used to investigate the fluid behavior inside and outside the synthetic jet actuator cavity, the impacts of thermoviscous losses on capturing the acoustic response of the actuator, and the viability of different modeling methods of diaphragms in computational simulations. The results capture the feedback from the fluid onto the diaphragm and highlight the need for careful acoustic modeling.

Validating a Reduced-Order Model for Synthetic Jet Actuators Using CFD and Experimental Data

Synthetic jet actuators (SJA) are emerging in various engineering applications, from flow separation and noise control in aviation to thermal management of electronics. A SJA oscillates a flexible membrane inside a cavity connected to a nozzle producing vortices. A complex interaction between the cavity pressure field and the driving electronics can make it difficult to predict performance. A reduced-order model (ROM) has been developed to predict the performance of SJAs. This paper applies this model to a canonical configuration with applications in flow control and electronics cooling, consisting of a single SJA with a rectangular orifice, emanating perpendicular to the surface. The practical implementation of the ROM to estimate the relationship between cavity pressure and jet velocity, jet velocity and diaphragm deflection and applied driving voltage is explained in detail. Unsteady Reynolds-averaged Navier Stokes computational fluid dynamics (CFD) simulations are used to assess the reliability of the reduced-order model. The CFD model itself has been validated with experimental measurements. The effect of orifice aspect ratio on the ROM parameters has been discussed. Findings indicate that the ROM is capable of predicting the SJA performance for a wide range of operating conditions (in terms of frequency and amplitude).

Characteristics of Vortex Ring Formation by Synthetic Jet Actuators in Different Cavities

This paper presents a baseline study of the development of turbulent flow separation for controlling aerodynamic phenomena, especially in the design of the vehicle body. The purpose of this study was to analyze the performance of synthetic jet actuators (SJAs) as one of the tools that can be used in reducing the flow controller separation area on the bluff body model of the vehicle. To get maximum results in the performance of the SJA, this research starts with characterizing the actuator, including changes in the shape of the cavity and orifice diameter. Cavity shapes tested were half-ball (B), tube (T) and cone (K), while orifice diameters of 3, 5 and 8 mm were examined. The study was conducted using both computational and experimental approaches. Results from both types of research methods were compared and displayed in graphical form. These results serve as a reference for determining future research. The experimental results, in the form of the flow rate for each type of cavity, determined the ability of different cavity conditions to form vortex rings, whereas in CFD simulations, the formation of vortex rings was demonstrated via the visualization of flow contours. Vortex rings occurred in cavity conditions B3, T3, T5, K3 and K5. Vortex rings were not formed on any type of cavity with an orifice having a diameter of 8 mm.

STUDY THE ORIFICE EFFECTS OF A SYNTHETIC JET ACTUATOR DESIGN

The synthetic jet actuator is an active flow control device that is used to improve the aerodynamic performance on working surfaces such as wings, helicopter blades and ground vehicles. The performance of synthetic jet actuator depends on the design of the orifice and cavity, and the oscillating driver. Piezoelectric diaphragm was used as an oscillating driver because of its small size and easier installation. The focus of this project is to study the effects of orifice size and shape for a synthetic jet actuator design. The effects were studied on circular and rectangular shapes, and different sizes of orifice. Meanwhile, the configurations of the cavity are fixed. Experiments were performed to determine the maximum pulse jet velocity and turbulence intensities of the jet coming out of the orifice, driven by the Piezoelectric diaphragm at different frequencies, at constant input voltage of 2V. The experiment mainly involved the measurement of the exit pulse jet velocity using a hot-wire anemometer. The results demonstrated that the circular orifice produced higher maximum pulse jet velocity and smaller sizes orifices, both circular and rectangular, results in higher velocity jets.

Qualitative Analysis of a Synthetic Jet Actuator with Different Cavity Thickness and Export Area

Present study investigates performance of synthetic jet actuator qualitatively. Its effectiveness of thickness of cavity, export area, working frequency and input voltage will be mainly studied by improved smoke flow visualization. The resonance frequency is also checked by the Helmholtz Resonance method and to well know interaction between the most effectiveness working frequency and cavity thickness. Experimental results indicated that higher input voltage makes higher smoke flow deflection angle and show the most obvious variation occurs at 200-400 Hz. Results also show the most efficiency working frequency is closed to resonance frequency of 400 Hz. The jet-to-wind velocity ratio of cross flow shows the same explanation. The ratio is inverse proportion to inflection level and proportion to penetration depth and turbulence intensity. Synthetic jet actuator with property cavity volume can cause higher exit velocity and increase velocity ratio R. It will increase penetration depth and cause higher turbulent intensity. Finally, the effect is more obvious and influence area is much larger.

Flow Visualization and Measurement of a Synthetic Jet Actuator Performance Using PIV System

This paper presents the performance of a piezoelectric Synthetic Jet Actuator (SJA) in quiescent flow. Pulse jet velocity and vorticity were taken as the parameter to evaluate the performance of SJA. PIV measurements on the jet flow at the orifice exit of a round SJA were conducted by varying the oscillating in frequency and voltage. The location of 5mm above orifice was identified as the optimum location for maximum pulse jet measurements. The maximum pulse jet velocity and vorticity obtained were 18.77 m/s and 242.5s-1. The PIV experiment showed that by varying oscillating frequency at fixed input voltage, the performance of SJA was greatly affected by Helmholtz resonance. While in the investigation of varying input voltage at fixed oscillating frequency, diaphragm defection was the parameter that affects the performance of the SJA. Besides, PIV measurement showed that the flow patterns of vortex structure formation were affected by the oscillating frequency and pulse jet velocity.

Cavity Effect of Synthetic Jet Actuators Based on Piezoelectric Diaphragm

An active flow control technology known as synthetic jet actuator (SJA) is a zero-net mass-flux device to create pulsed jet that produces momentum to its surroundings and uses a vibrating diaphragm inside the cavity to generate an oscillatory flow through a small orifice. The performance of SJA depends on the design of an orifice and cavity, and oscillating membrane. SJA design based on piezoelectric diaphragm used in this project because of their size, lightweight, no need for external air supply, without the pipe complex, fast response time and low power consumption. This paper describes the cavity effect to SJA designs and experiments were performed to determine the air jet velocity produced through the orifice using a hot-wire anemometer at a different cavity thickness. The results demonstrate that the jet velocity increase would be better if the cavity thickness is reduced. However, more studies are needed to optimize the size of cavity and orifice for appropriate applications.

Evaluation of synthetic jet actuators design performance

PurposeThe purpose of this paper is to evaluate the synthetic jet actuator design's performance based on piezoelectric diaphragms that can be appropriately used for flow separation control.Design/methodology/approachDesign the synthetic jet actuators by means of estimating the several parameters and non‐dimensional parameters. Understanding the relationship and coupling effects of these parameters on the actuator to produce exit air jet required. Experiments were conducted to measure the exit air jet velocity using a hot‐wire anemometry and determine the good operational frequencies and voltages of the actuators for different cavity volume.FindingsThe performance of synthetic jet actuator is not consistent to a particular given frequency and it depends on design configurations. Each actuator will give a very good speed for a certain frequency. The results show that the exit air jet velocity increases would be better if the cavity volume is reduced and if the input voltage is increased to certain limits.Research limitations/implicationsThe limit of input voltage for the actuators that can be achieved for good jet speed is 2V of about 205V output voltage for each frequency. The jet speed obtained is sufficient enough to control the separation for an aircraft which has a small wing chord and low speed. Therefore, more studies are needed to optimize the sizes of an orifice and cavity, and the selection of piezoelectric diaphragm.Practical implicationsThe study helps in establishing a flow control device for controlling flow separation, especially on airfoils.Originality/valueDesign the synthetic jet actuators based on piezoelectric diaphragm for applications of flow separation control.

Performance of synthetic jet actuators based on hybrid and double-acting principles

The design of the discussed fluid jet actuator followed two ideas: a double-acting operation of reciprocating pumps, and a hybrid synthetic jet (HSJ) actuation. The entire actuator consists of two basic parts, namely the front (central) and rear chambers, from which fluid is displaced by the opposite sides of the same diaphragm. The actuator operates in a double-acting (antiphase) regime with air as the working fluid. The central chamber generates the standard (zero-net-mass-flux) axisymmetric synthetic jet (SJ), while the rear chamber generates system of several non-zero-net-mass-flux HSJs arranged around the central SJ. A number of variants of HSJs with different geometry were designed, manufactured and tested. Their behavior was investigated experimentally using the smoke visualization, reaction force measurement, hot-wire anemometry, and naphthalene sublimation technique. The tests confirm the efficiency of the present design.