# LEM Characterization of Synthetic Jet Actuators Driven by Piezoelectric Element: A Review

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Lumped Element Models

#### 2.1. Fluid Dynamic LEM

#### 2.2. Analytical Stationary Solution

- if the structural resonance frequency equals the Helmholtz frequency (i.e., $\beta =1$), there is a $\pi /2$ phase difference between the diaphragm and the jet,$${\left[{\varphi}_{{V}_{w}}-{\varphi}_{U}\right]}_{\omega ={\omega}_{w}}^{CF=0}={\displaystyle \frac{\pi}{2}}\phantom{\rule{1.em}{0ex}}\phantom{\rule{1.em}{0ex}}\phantom{\rule{1.em}{0ex}}\beta =1$$
- if the structural frequency is much higher than the resonance frequency ($\beta \gg 1$), then:$$\underset{\beta \to +\infty}{lim}{\left.{\varphi}_{U}\right|}_{\omega ={\omega}_{w}}^{CF=0}=-{\displaystyle \frac{\pi}{2}}$$and the diaphragm and the jet are out of phase by $\pi $$${\left[{\varphi}_{{V}_{w}}-{\varphi}_{U}\right]}_{\omega ={\omega}_{w}}^{CF=0}=\pi \phantom{\rule{1.em}{0ex}}\phantom{\rule{1.em}{0ex}}\phantom{\rule{1.em}{0ex}}\beta \gg 1$$
- if the structural resonance frequency is very small ($\beta \ll 1$), then the compressible effects are negligible and the diaphragm and the jet are in phase with each other:$${\left[{\varphi}_{{V}_{w}}-{\varphi}_{U}\right]}_{\omega ={\omega}_{w}}^{CF=0}=0\phantom{\rule{1.em}{0ex}}\phantom{\rule{1.em}{0ex}}\phantom{\rule{1.em}{0ex}}\beta \ll 1$$

#### 2.3. Transduction Approach

#### 2.4. Dimensionless Equations

## 3. Comparison of LEM Results

## 4. Performances

#### 4.1. Effect of the Coupling of the Oscillators

#### 4.2. Effect of the Voltage

#### 4.3. Effect of the Orifice Length

## 5. Efficiency of Piezo-Driven Devices

- $\overline{\mathsf{\Delta}E}$ is the total energy variation. Note that this term is null because, for each cycle, there is no change for ${E}_{w}$ and ${E}_{o}$, with ${E}_{w}$ and ${E}_{o}$ being the diaphragm energy and the kinetic energy of air issuing from the orifice respectively. The diaphragm energy takes into account both kinetic and elastic strain contributions.
- ${\overline{P}}_{e}$ is the electrodynamic power provided to the membrane by the applied voltage.
- ${\overline{P}}_{m}$ is the mechanical power due to the work done by the differential pressure ${p}_{i}$ which acts on the wall surface ${A}_{w}$ and on the orifice surface ${A}_{o}$. By using Equation (10), it can be shown that this term is proportional to $\frac{1}{2}({{p}_{i}}^{2}\left(T\right)-{{p}_{i}}^{2}\left(0\right))$ and, therefore, it does not give any contribution because ${p}_{i}$ assumes the same value at the beginning and end of each cycle. One can reach the same result by observing that the pressure work is conservative by definition.
- ${\overline{D}}_{s}$ is the power dissipation due to the structural damping effects of the diaphragm. Note that, according to standard notations, ${c}_{wt}=2{m}_{wt}{\zeta}_{w}{\omega}_{w}$.
- ${\overline{D}}_{f}$ is the power dissipation due to the head loss of fluid dynamics type at the orifice.
- ${\overline{P}}_{k}$ is the kinetic power of air flow at the orifice. Note explicitly that the kinetic power here refers by definition to the entire cycle, i.e., suction phase included.

## 6. Conclusions

## Acknowledgments

## Author Contributions

## Conflicts of Interest

## References

- Glezer, A.; Amitay, M. Synthetic Jets. Annu. Rev. Fluid Mech.
**2002**, 34, 503–529. [Google Scholar] [CrossRef] - Cattafesta, L., III; Sheplak, M. Actuators for Active Flow Control. Annu. Rev. Fluid Mech.
**2010**, 43, 247–272. [Google Scholar] [CrossRef] - Smith, B.; Glezer, A. Jet vectoring using synthetic jets. J. Fluid Mech.
**2002**, 458, 1–34. [Google Scholar] [CrossRef] - Glezer, A. Some aspects of aerodynamic flow control using synthetic-jet actuation. Philos. Trans. R. Soc. Lond. A
**2010**, 369, 1476–1494. [Google Scholar] [CrossRef] [PubMed] - Buren, V.T.; Leong, C.; Whalen, E. Impact of orifice orientation on a finite-span synthetic jet interaction with a crossflow. Phys. Fluid.
**2016**, 28, 1–20. [Google Scholar] [CrossRef] - Wang, H.; Menon, S. Fuel-Air Mixing Enhancement by Synthetic Microjets. AIAA J.
**2010**, 39, 2308–2319. [Google Scholar] [CrossRef] - Tamburello, D.; Amitay, M. Active manipulation of a particle-laden jet. Int. J. Multiph. Flow
**2008**, 34, 829–851. [Google Scholar] [CrossRef] - Pavlova, A.; Amitay, M. Electronic Cooling Using Synthetic Jet Impingement. Phys. Fluid
**2006**, 128, 897–907. [Google Scholar] [CrossRef] - Chaudhari, M.; Puranik, B.; Agrawal, A. Heat transfer characteristics of synthetic jet impingement cooling. Int. J. Heat Mass Transf.
**2010**, 53, 1057–1069. [Google Scholar] [CrossRef] - Pavlova, A.; Otani, K.; Amitay, M. Active control of sprays using a single synthetic jet actuator. Int J. Heat Fluid Flow
**2007**, 29, 131–148. [Google Scholar] [CrossRef] - Marchitto, L.; Valentino, G.; Chiatto, M.; de Luca, L. Water spray flow characteristics under synthetic jet driven by a piezoelectric actuator. J. Phys.
**2017**, 778, 1–14. [Google Scholar] [CrossRef] - Finley, T.; Mohseni, K. Micro pulsatile jets for thrust optimization. In Proceedings of the ASME 2004 International Mechanical Engineering Congress and Exposition, Anaheim, CA, USA, 13–20 November 2004. [Google Scholar]
- Parviz, B.; Najafi, K.; Muller, M.; Bernal, L.; Washabaugh, P. Electrostatically driven synthetic microjet arrays as a propulsion method for micro flight. Part I: Principles of operation, modeling, and simulation. Microsyst. Technol.
**2005**, 11, 1214–1222. [Google Scholar] [CrossRef] - Otani, K.; Moore, J.; Gressick, W.; Amitay, M. Active Yaw Control of a Ducted Fan-Based MAV using Synthetic Jets. Int. J. Flow Control
**2009**, 1, 29–42. [Google Scholar] [CrossRef] - Smith, B.; Glezer, A. The formation and the evolution of synthetic jets. Phys. Fluid.
**1998**, 10, 2281–2297. [Google Scholar] [CrossRef] - Cater, J.; Soria, J. The evolution of round zero-net-mass-flux jets. J. Fluid Mech.
**2002**, 472, 167–200. [Google Scholar] [CrossRef] - Mohseni, K.; Mittal, R. Synthetic Jets: Fundamentals and Applications; Taylor & Francis Group LCC.: Abingdon, England, 2015. [Google Scholar]
- Rumsey, C.L.; Gatski, T.B.; Sellers, W.L., III; Vatsa, V.N.; Viken, S.A. Summary of the 2004 Computational Fluid Dynamics Validation Workshop on Synthetic Jets. AIAA J.
**2006**, 44, 194–207. [Google Scholar] [CrossRef] - Dandois, J.; Garnier, E.; Sagaut, P. Numerical simulation of active separation control by a synthetic jet. J. Fluid Mech.
**2007**, 574, 25–58. [Google Scholar] [CrossRef] - Lardeau, S.; Leschziner, M.A. The interaction of round synthetic jets with a turbulent boundary layer separating from a rounded ramp. J. Fluid Mech.
**2011**, 683, 172–211. [Google Scholar] [CrossRef] - McCormick, D. Boundary layer separation control with directed synthetic jets. In Proceedings of the 38th Aerospace Sciences Meeting and Exhibit, Aerospace Sciences Meetings, Reno, NV, USA, 10–13 January 2000. [Google Scholar]
- Prasad, S. Two-Port Electroacoustic Model of Piezoelectric Composite Circular Plate. Master’s Thesis, University of Florida, Gainesville, FL, USA, 2002. [Google Scholar]
- Gallas, Q.; Holman, R.; Nishida, T.; Carroll, B.; Sheplak, M.; Cattafesta, L. Lumped Element Modeling of Piezoelectric-Driven Synthetic Jet Actuators. AIAA J.
**2003**, 41, 240–247. [Google Scholar] [CrossRef] - Prasad, S.; Gallas, Q.; Horowitz, S.; Homeijer, B. Analytical Electroacoustic Model of a Piezoelectric Composite Circular Plate. AIAA J.
**2006**, 41, 240–247. [Google Scholar] [CrossRef] - Persoons, T. General Reduced-Order Model to Design and Operate Synthetic Jet Actuators. AIAA J.
**2012**, 50, 916–927. [Google Scholar] [CrossRef] - Tang, H.; Zhong, S. Lumped element modelling of synthetic jet actuators. Aerosp. Sci. Technol.
**2009**, 13, 331–339. [Google Scholar] [CrossRef] - Agashe, J.; Arnold, D.; Cattafesta, L. Development of Compact Electrodynamic Zero-Net Mass-Flux Actuators. In Proceedings of the 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition, Orlando, FA, USA, 5–8 January 2009. [Google Scholar]
- Sawant, S.; Oyarzun, M.; Sheplak, M.; Cattafesta, L., III; Arnold, D.P. Modeling of Electrodynamic Zero-Net Mass-Flux Actuators. AIAA J.
**2012**, 50, 1347–1359. [Google Scholar] [CrossRef] - Luo, Z.; Xia, Z.; Liu, B. New Generation of Synthetic Jet Actuators. AIAA J.
**2006**, 44, 2418–2419. [Google Scholar] [CrossRef] - Arunajatesan, S.; Oyarzun, M.; Palaviccini, M.; Cattafesta, L. Modeling of Zero-Net Mass-Flux Actuators for feedback Flow Control. In Proceedings of the 47th AIAA Aerospace Sciences Meeting Including The New Horizons Forum and Aerospace Exposition, Orlando, FA, USA, 5–8 January 2009. [Google Scholar]
- Sharma, R. Fluid-Dynamic-Based Analytical Model for Synthetic Jet Actuation. AIAA J.
**2007**, 45, 1841–1847. [Google Scholar] [CrossRef] - De Luca, L.; Girfoglio, M.; Coppola, G. Modeling and Experimental Validation of the Frequency Response of Synthetic Jet Actuators. AIAA J.
**2014**, 52, 1733–1748. [Google Scholar] [CrossRef] - De Luca, L.; Girfoglio, M.; Chiatto, M.; Coppola, G. Scaling properties of resonant cavities driven by piezo-electric actuators. Sens. Actuators A Phys.
**2016**, 247, 465–474. [Google Scholar] [CrossRef] - Rathnasingham, R.; Breuer, K. Coupled Fluid-Structure Characteristics of Actuators for Flow Control. AIAA J.
**1997**, 35, 832–837. [Google Scholar] [CrossRef] - Kinsler, L.; Frey, A.; Coppens, A.; Sanders, J. Fundamentals of Acoustics, 4th ed.; Wiley: Hoboken, NJ, USA, 1999. [Google Scholar]
- Krishnan, G.; Mobseni, K. Axisymmetric synthetic jets: An experimental and theoretical examination. AIAA J.
**2009**, 47, 2273–2283. [Google Scholar] [CrossRef] - Gomes, L.; Crowther, W.J.; Wood, N. Towards a practical piezoceramic diaphragm based synthetic jet actuator–effect of chamber and orifice depth on actuator peak velocity. In Proceedings of the 3rd AIAA Flow control conference, San Francisco, CA, USA, 5–8 June 2006. [Google Scholar]
- Senturia, S. Microsystem Design; Kluwer Academic Publishers: Berlin, Germany, 2001. [Google Scholar]
- Girfoglio, M.; Greco, C.; Chiatto, M.; de Luca, L. Modelling of efficiency of synthetic jet actuators. Sens. Actuator. A Phys.
**2015**, 233, 512–521. [Google Scholar] [CrossRef] - Moffat, R. Describing the uncertainties in experimental results. Exp. Therm. Fluid Sci.
**1988**, 1, 3–17. [Google Scholar] [CrossRef] - Gil, P.; Strzelczyk, P. Performance and efficiency of loudspeaker driven synthetic jet actuator. Exp. Therm. Fluid Sci.
**2016**, 76, 163–174. [Google Scholar] [CrossRef] - Kooijman, G.; Ouweltjes, O. Finite difference time domain electroacoustic model for synthetic jet actuators including nonlinear flow resistance. J. Acoust. Soc. Am.
**2009**, 125, 1911–1918. [Google Scholar] [CrossRef] [PubMed] - Crowther, W.J.; Gomes, L. An evaluation of the mass and power scaling of synthetic jet actuator flow control technology for civil transport aircraft applications. Proc. Inst. Mech. Eng. Part I Syst. Control Eng.
**2008**, 222, 357–372. [Google Scholar] [CrossRef] - Li, R.; Sharma, R.; Arik, M. Energy conversion efficiency of synthetic jets. In Proceedings of the ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, Portland, OR, USA, 6–8 July 2011. [Google Scholar]
- Kordík, J.; Trávníček, Z. Optimal diameter of nozzles of synthetic jet actuators based on electrodynamic transducers. Exp. Therm. Fluid Sci.
**2017**, 86, 281–294. [Google Scholar] [CrossRef] - Rowley, C.; Dawson, S. Model Reduction for Flow Analysis and Control. Annu. Rev. Fluid Mech.
**2017**, 49, 387–417. [Google Scholar] [CrossRef]

**Figure 1.**Typical Synthetic Jet device driven by a piezoelectric element. (

**left**) top view with orifice; (

**right**) bottom view with metallic shim and piezodisk.

**Figure 3.**Aluminum shim diaphragm deflections detected by laser vibrometer. (

**a**) fundamental mode (0,1) for actuation frequency $f=1555$ Hz; (

**b**) mode (2,2) for $f=5370$ Hz. ${V}_{ac}=6$ V. Courtesy of University of Naples.

**Figure 4.**Plan view of device response in peak velocity as a function of the chamber height $H/{d}_{o}$. Coupled structural frequency (black line) and Helmholtz frequency (orange line) are depicted. Reprinted with permission from [37].

**Figure 6.**Amplification factor of jet peak velocity for decoupled oscillators ($CF=0$) and $\omega ={\omega}_{w}$, Equation (29). Continuous red line is for ${\zeta}_{{U}_{\mathrm{inc}}}=1$, dotted-dashed blue line for ${\zeta}_{{U}_{\mathrm{inc}}}=0.1$, dashed black line for ${\zeta}_{{U}_{\mathrm{inc}}}=0.01$.

**Figure 9.**Comparison of experimental data and Lumped Element Modeling (LEM) results of peak jet velocity for two actuators, (a) case 1 and (b) case 2, reprinted from [31]. Blue markers are experimental data from Gallas et al. [23], blue line represents LEM by Gallas et al. [23], red line LEM by Sharma [31]. Reprinted with permission from [31].

**Figure 10.**Numerical, analytical and experimental comparison of saddle point velocity for (

**a**) the brass actuator ($H/do=0.75$, ${V}_{ac}=50$ V) and (

**b**) the aluminum actuator ($H/do=0.8$, ${V}_{ac}=50$ V). Blue solid lines are numerical results, black dash-dotted curves analytical ones and red markers experimental data with their uncertainty bars. Reprinted with permission from [33].

**Figure 12.**Frequency response of saddle point velocity for the brass actuator at ${V}_{a}=35$ V; black dotted line refers to $H/{d}_{o}=0.5$, magenta dash-dotted line to $H/{d}_{o}=1$, blue dashed line to $H/{d}_{o}=\phantom{\rule{3.33333pt}{0ex}}1.5$, red solid line to $H/{d}_{o}=2.5$. The straight line refers to Equation (47). Reprinted with permission from [33].

**Figure 13.**Frequency response of saddle point velocity for the aluminum actuator at ${V}_{a}=35$ V; black dotted line refers to $H/{d}_{o}=0.5$, magenta dash-dotted line to $H/{d}_{o}=1$, blue dashed line to $H/{d}_{o}=1.5$, red solid line to $H/{d}_{o}=2.5$. The straight line refers to Equation (47). Reprinted with permission from [33].

**Figure 14.**Spatially- and temporally-averaged momentum velocity for various cavity heights. Blue square markers are for $H=20$ mm, red circles for $H=40$ mm and black diamonds for $H=60$ mm. Reprinted with permission from [41].

**Figure 15.**SJ peak velocity response as a function of excitation frequency at resonance frequencies ($h/{d}_{o}=2.1$ and $H/{d}_{o}=0.56$). Blue data points are for diaphragm resonance, red data for acoustic resonance. Reprinted with permission from [43].

**Figure 16.**Electric–fluid energy conversion efficiency as a function of excitation frequency. Blue line refers to ${V}_{ac}=90$ V, red line to ${V}_{ac}=250$ V ($h/{d}_{0}=2.1$ and $H/{d}_{0}=0.56$). Reprinted with permission from [43].

**Figure 17.**Frequency response of saddle point flow velocity for (

**a**) the aluminum actuator and (

**b**) the brass actuator at different equivalent length; red solid line refers to ${l}_{e}/d=1$, blue dashed line to ${l}_{e}/d=2$ and black dotted line to ${l}_{e}/d=3$.

Energy Domain | Effort, $\mathit{e}\left(\mathit{t}\right)$ | Flow, $\mathit{f}\left(\mathit{t}\right)$ |
---|---|---|

Mechanical | Force, F | Velocity, U |

Mechanical | Pressure, ${p}_{i}$ | Volumetric flow rate, Q |

Electrical | Voltage, ${V}_{ac}$ | Current, I |

$Re={\displaystyle \frac{\overline{U}{d}_{o}}{\nu}}$ | $S={\displaystyle \frac{\omega {d}_{o}^{2}}{\nu}}$ | $\frac{{d}_{o}}{{d}_{w}}$ | $\frac{H}{{d}_{o}}$ | $\frac{{l}_{e}}{H}$ | $\frac{{m}_{c}}{{m}_{wt}}$ | $CF={\displaystyle \frac{{\omega}_{wc}^{2}}{{\omega}_{w}^{2}}}$ | $St={\displaystyle \frac{\omega H}{c}}$ |

**Table 3.**Features of the devices studied by Gallas et al. [23].

Property | Case 1 | Case 2 | |
---|---|---|---|

Geometry | Shim diameter (mm) | 23 | 37 |

Shim thickness (mm) | $0.15$ | $0.10$ | |

Piezo-electric diameter (mm) | 20 | 25 | |

Piezo-electric thickness (mm) | $0.08$ | $0.11$ | |

Cavity diameter (mm) | 23 | 37 | |

Cavity height (mm) | $5.76$ | $4.65$ | |

Orifice diameter (mm) | $1.65$ | $0.84$ | |

Orifice length (mm) | $1.65$ | $0.84$ | |

$H/{d}_{o}$ | $3.5$ | $5.5$ | |

${l}_{e}/{d}_{o}$ | 1 | 1 | |

Shim (brass) | Young’s Module (Pa) | $8.963\times {10}^{10}$ | $8.963\times {10}^{10}$ |

Poisson’s Module | $0.324$ | $0.324$ | |

Density (Kg/m^{3}) | 8700 | 8700 | |

Piezo-electric | Young’s Module (Pa) | $6.3\times {10}^{10}$ | $6.3\times {10}^{10}$ |

Poisson’s Module | $0.31$ | $0.31$ | |

Density (Kg/m^{3}) | 7700 | 7700 | |

Frequency response | ${f}_{w}$ (Hz) | 2114 | 632 |

${f}_{1}$ (Hz) | 2167 | 324 | |

${f}_{H}$ (Hz) | 941 | 452 | |

${f}_{2}$ (Hz) | 918 | 880 | |

$CF$ | $0.07$ | $2.85$ |

**Table 4.**Features of the devices studied by de Luca et al. [33].

Property | Brass | Aluminum | ||
---|---|---|---|---|

Geometry | Shim diameter (mm) | 41 | 80 | |

Shim thickness (mm) | $0.4$ | $0.25$ | ||

Piezo-electric diameter (mm) | $31.8$ | $63.5$ | ||

Piezo-electric thickness (mm) | $0.191$ | $0.191$ | ||

Cavity diameter (mm) | 41 | 80 | ||

Cavity height (mm) | $1.5$ | 4 | ||

Orifice diameter (mm) | 2 | 5 | ||

Orifice length (mm) | 2 | 2 | ||

$H/{d}_{o}$ | $0.75$ | $0.8$ | ||

${l}_{e}/{d}_{o}$ | 1 | $0.4$ | ||

Shim | Young’s Module (Pa) | $9.7\times {10}^{10}$ | $7.31\times {10}^{10}$ | |

Poisson’s Module | $0.36$ | $0.31$ | ||

Density (Kg/m^{3}) | 8490 | 2780 | ||

Diaphragm damping ratio | $0.03$ | $0.03$ | ||

Piezo-electric | Young’s Module (Pa) | $6.6\times {10}^{10}$ | $6.6\times {10}^{10}$ | |

Poisson’s Module | $0.31$ | $0.31$ | ||

Density (Kg/m^{3}) | 8700 | 7800 | ||

Frequency response | ${f}_{w}$ (Hz) | 1667 | 432 | |

${f}_{1}$ (Hz) | 1877 | 344 | ||

${f}_{h}$ (Hz) | 1004 | 752 | ||

${f}_{2}$ (Hz) | 891 | 945 | ||

$CF$ | $0.19$ | $1.38$ |

**Table 5.**Efficiencies of brass actuator at modified resonance structural frequency. $CF$ = 0.06. Reprinted with permission from [39].

${\mathit{V}}_{\mathit{ac}}$ (V) | ${\mathit{\eta}}_{\mathit{k}}$ (%) | ${\mathit{\eta}}^{\mathit{*}\mathit{*}}$ (%) | ${\mathit{\eta}}^{\mathit{*}}$ (%) |
---|---|---|---|

25 | 4.7 | 85.5 | 5.5 |

30 | 5.3 | 85.3 | 6.3 |

35 | 5.9 | 85 | 6.9 |

40 | 6.4 | 84.8 | 7.5 |

45 | 6.8 | 85.5 | 7.9 |

50 | 7.3 | 88.6 | 8.2 |

55 | 7.5 | 86.6 | 8.7 |

60 | 7.6 | 85.6 | 8.9 |

65 | 7.9 | 87.1 | 9.1 |

70 | 8.1 | 87.8 | 9.2 |

75 | 8.5 | 83.7 | 10.1 |

**Table 6.**Efficiencies of aluminum actuator at modified resonance Helmholtz frequency. $CF$ = 1.88. Reprinted with permission from [39].

${\mathit{V}}_{\mathit{ac}}$ (V) | ${\mathit{\eta}}_{\mathit{k}}$ (%) | ${\mathit{\eta}}^{\mathit{*}\mathit{*}}$ (%) | ${\mathit{\eta}}^{\mathit{*}}$ (%) |
---|---|---|---|

25 | 79.2 | 86.6 | 91.6 |

30 | 79.5 | 87.6 | 90.7 |

35 | 79.7 | 88.2 | 90.4 |

40 | 80.7 | 86.4 | 93.4 |

45 | 80.3 | 87.7 | 91.6 |

50 | 80.2 | 87.9 | 91.3 |

55 | 82.3 | 82.3 | 88.9 |

60 | 81.8 | 87.5 | 93.4 |

65 | 81.8 | 87.8 | 92.1 |

70 | 80.1 | 87.3 | 91.8 |

75 | 81 | 87.9 | 92.2 |

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**MDPI and ACS Style**

Chiatto, M.; Capuano, F.; Coppola, G.; De Luca, L.
LEM Characterization of Synthetic Jet Actuators Driven by Piezoelectric Element: A Review. *Sensors* **2017**, *17*, 1216.
https://doi.org/10.3390/s17061216

**AMA Style**

Chiatto M, Capuano F, Coppola G, De Luca L.
LEM Characterization of Synthetic Jet Actuators Driven by Piezoelectric Element: A Review. *Sensors*. 2017; 17(6):1216.
https://doi.org/10.3390/s17061216

**Chicago/Turabian Style**

Chiatto, Matteo, Francesco Capuano, Gennaro Coppola, and Luigi De Luca.
2017. "LEM Characterization of Synthetic Jet Actuators Driven by Piezoelectric Element: A Review" *Sensors* 17, no. 6: 1216.
https://doi.org/10.3390/s17061216