Synthetic Jet Actuator Cavity Acoustics: Helmholtz Versus Quarter-Wave Resonance

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Tyler Van Buren ◽  
Edward Whalen ◽  
Michael Amitay
Keyword(s):  
Acoustic Resonance ◽  
Synthetic Jet ◽  
Cavity Resonance ◽  
Synthetic Jet Actuator ◽  
Acoustic Cavity ◽  
Wave Resonance ◽  
Cavity Resonances ◽  
Quarter Wave ◽  
Cavity Acoustics ◽  
The Impact

The impact of cavity geometry on the source of acoustic resonance (Helmholtz or quarter-wave) for synthetic jet type cavities is presented. The cavity resonance was measured through externally excited microphone measurements. It was found that, for pancake-shaped cavities, the Helmholtz resonance equation was inadequate (off by more than 130%) at predicting the acoustic cavity resonances associated with synthetic jet actuation, whereas a two-dimensional quarter-wave resonance was accurate to 15%. The changes in the geometry (cavity diameter, cavity height, and orifice length) could alter the cavity resonance by up to 50%, and a finite element solver was accurate at predicting this resonance in all cases. With better knowledge of the phenomena governing the acoustic resonance, prediction of the cavity resonance can become more accurate and improvements to current prediction tools can be made.

Experimental Investigation on the Impact of Distorted Signal on Synthetic Jet

2016 ◽  
Vol 831 ◽  
pp. 104-111
Author(s):  
Paweł Gil
Keyword(s):  
Input Signal ◽  
Average Velocity ◽  
Fluid Velocity ◽  
Synthetic Jet ◽  
The Novel ◽  
Synthetic Jet Actuator ◽  
Negative Effect ◽  
Novel Method ◽  
Conventional Cooling ◽  
The Impact

Effective techniques for cooling electronic devices must deal with increasing heat loads associated with higher heat flux density. Many conventional cooling techniques like fan are reaching the limits of their effectiveness and shape. The novel method of heat transfer enhancement is synthetic jet. In this paper experimental results are presented. Synthetic jet actuator consist of STX 6.5 inch speaker installed in metacrylate chamber with circular orifice. The actuator was powered with signal from amplifier. The signal consist of basic sinusoidal function and THD noise added with some amplitude. The root mean square of signal voltage was constant 4V. The properties of synthetic jet were measured using constant temperature thermo-anemometer. Instantaneous velocity of air was measured in the orifice center and compared with input signal. Additional RMS and average velocity of air were measured. Measurement revealed that input signal of synthetic jet generator can contain some noise without effect on RMS and average velocity of air in the orifice. The THD less than 1% does not cause negative effect on synthetic jet fluid velocity.

Experimental Study of the Acoustic Cavity Resonance in Automobile Tire Dynamic Response

1999 ◽  
Author(s):  
Molly J. Subler ◽  
Richard F. Keltie ◽  
Dimitri Tsihlas
Keyword(s):  
Resonance Frequency ◽  
Transfer Functions ◽  
Dynamic Stiffness ◽  
Acoustic Resonance ◽  
Cavity Resonance ◽  
Inflation Pressure ◽  
Automobile Tire ◽  
Acoustic Cavity ◽  
Cavity Modes ◽  
Helium Gas

Abstract A series of tests were conducted to measure the dynamic stiffness transfer functions between the wheel center of a rim-mounted tire and the contact patch. Of particular interest was the interaction between the tire acoustic cavity mode and the modes of the tire/rim system. By varying the concentration of helium gas within the tire, it was possible to sweep the acoustic resonance through a group of rim/tire resonances. These results showed that there is relatively weak interaction between the cavity modes and the tire/rim modes. It was found that the resonance frequency of the cavity shifts downward with increasing tire load, and that only the z-direction dynamic stiffness is affected by load. Changes in inflation pressure were found to have no effect on the cavity resonance frequency, and increases in inflation pressure led to significant changes only in the x-direction dynamic stiffness. A simple analytical model of a coupled structural/acoustic system was found to produce results similar to those observed in the tire testing.

Plane Wave Resonance in the Tire Air Cavity as a Vehicle Interior Noise Source

1995 ◽  
Vol 23 (1) ◽  
pp. 2-10 ◽  
Author(s):  
J. K. Thompson
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Interior Noise ◽  
Cavity Resonance ◽  
Test Results ◽  
Vehicle Interior ◽  
Air Cavity ◽  
Vehicle Interior Noise ◽  
Wave Resonance ◽  
Resonance Frequencies

Abstract Vehicle interior noise is the result of numerous sources of excitation. One source involving tire pavement interaction is the tire air cavity resonance and the forcing it provides to the vehicle spindle: This paper applies fundamental principles combined with experimental verification to describe the tire cavity resonance. A closed form solution is developed to predict the resonance frequencies from geometric data. Tire test results are used to examine the accuracy of predictions of undeflected and deflected tire resonances. Errors in predicted and actual frequencies are shown to be less than 2%. The nature of the forcing this resonance as it applies to the vehicle spindle is also examined.

scholarly journals Analysis of Tire Acoustic Cavity Resonance Energy Transmission Characteristics in Wheels Based on Power Flow Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3979
Author(s):  
Wei Zhao ◽  
Yuting Liu ◽  
Xiandong Liu ◽  
Yingchun Shan ◽  
Xiaojun Hu
Keyword(s):  
Power Flow ◽  
Resonance Energy ◽  
Cavity Resonance ◽  
Propagation Path ◽  
Material Structure ◽  
Transmission Characteristics ◽  
Energy Transmission ◽  
Flow Method ◽  
Acoustic Cavity ◽  
Power Flow Method

As a kind of low-frequency vehicle interior noise, tire acoustic cavity resonance noise plays an important role, since the other noise (e.g., engine noise, wind noise and friction noise) has been largely suppressed. For the suspension system, wheels stand first in the propagation path of this energy. Therefore, it is of great significance to study the influence of wheel design on the transmission characteristics of this vibration energy. However, currently the related research has not received enough attention. In this paper, two sizes of aluminum alloy wheel finite element models are constructed, and their modal characteristics are analyzed and verified by experimental tests simultaneously. A mathematically fitting sound pressure load model arising from the tire acoustic cavity resonance acting on the rim is first put forward. Then, the power flow method is applied to investigate the resonance energy distribution and transmission characteristics in the wheels. The structure intensity distribution and energy transmission efficiency can be described and analyzed clearly. Furthermore, the effects of material structure damping and the wheel spoke number on the energy transmission are also discussed.

scholarly journals Cephalopod‐Inspired Swimming Robot Using Dielectric Elastomer Synthetic Jet Actuator

2020 ◽  
Vol 22 (4) ◽  
pp. 2070014
Author(s):  
Chao Tang ◽  
Wentao Ma ◽  
Bo Li ◽  
Mingliang Jin ◽  
Hualing Chen
Keyword(s):  
Dielectric Elastomer ◽  
Synthetic Jet ◽  
Synthetic Jet Actuator

Analytical Model: Characteristics of Nanosecond Pulsed Plasma Synthetic Jet Actuator in Multiple-Pulsed Mode

2017 ◽  
Vol 9 (2) ◽  
pp. 439-462 ◽  
Author(s):  
Zheng Li ◽  
Zhiwei Shi ◽  
Hai Du
Keyword(s):  
Flow Characteristics ◽  
Simulation Method ◽  
Synthetic Jet ◽  
Blast Waves ◽  
Pulsed Plasma ◽  
Synthetic Jet Actuator ◽  
Field Coupling ◽  
Neutral Gas ◽  
Pulsed Mode ◽  
Physical Principles

AbstractMulti-field coupling simulation method based on the physical principles is used to simulate the discharge characteristics of nanosecond pulsed plasma synthetic jet actuator. Considering the effect of the energy transferring for air, the flow characteristics of nanosecond pulsed plasma synthetic jet actuator are simulated. The elastic heating sources and ion joule heating sources are the two main sources of energy. Through the collisions, the energy of ions is transferred to the neutral gas quickly. The flow characteristics of a series of blast waves and the synthetic jet which erupt from the plasma synthetic jet (PSJ) actuator are simulated. The blast wave not only promotes outward, but also accelerates the gas mixing the inhaled gas from the outside cavity with the residual gas inside the cavity. The performances of PSJ actuator fluctuate in the first three incentive cycles and become stable after that.

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