Research in WAVE LAB include (but not limited to) the following topics:

1. Acoustic Metasurface

2. Acoustic Black Hole

3. Aeroacoustic Metamaterials

4. Prediction and Reduction of Fan Noise

 

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1. Acoustic Metasurface

Controlling low-frequency sound with a subwavelength-scaled structure is an important but challenging issue. The acoustic metasurface is a periodic structure that can manipulate low-frequency sound with ultra-thin thickness. We propose new designs of acoustic metasurface and apply such designs to many engineering problems such as perfect sound absorption.

 

2. Acoustic Black Hole

As lights cannot not escape from a black hole, incident elastic waves cannot escape from an acoustic black hole (ABH). The ABH is a wedge-shaped structure whose thickness is reduced to zero by the power-law. Owing to its extraordinary geometry, the ABH slows down the group speed of elastic waves to zero and focuses the energy of the elastic waves toward its tip. In WAVELAB, we develop mathematical theories and designs for the ABH customized to various industrial applications. For instance, we proposed an Archimedean spiral ABH to enhance the space efficiency while maintaining the damping performance of the ABH. The ultimate goal is to provide an efficient passive control of structural vibrations by using a lightweight structure.

 

3. Aeroacoustic Metamaterials

Acoustic metamaterials are materials exhibiting a property that is not found in nature. The unusual property of the acoustic metamaterial is affected by moving medium, we theoretically and numerically examine the effects of moving medium on sound propagation around the metamaterials in order to propose new designs of aerodynamic systems such as new convective clock, low-noise wind turbine, and urban air mobility.

 

4. Prediction and Reduction of Fan Noise

Fast and accurate prediction and effective reduction of noise radiated from rotating fans are very important technologies in the industries. In cooperation with LG electronics, we are currently developing a program to predict the tonal and broadband fan noise with efficiency and accuracy. In addition, we are trying to apply acoustic meta-structures to reduce the fan noise effectively.

 

J. Y. Lee and W. Jeon
Wave-based analysis of the cut-on frequency of curved acoustic black holes
Journal of Sound and Vibration, 2021-02, Vol. 492, No. 0, pp. 115731~ 0

T.S. Oh and W. Jeon
Bandgap characteristics of phononic crystals in steady and unsteady flows
The Journal of the Acoustical Society of America,, 2020-09, Vol. 148, No. 3, pp. 1181~ 1192

D. Yu, W. Jeon, and S.J. Kim
Analytic study on pressure drop and heat transfer characteristics for low Reynolds number flow in spirally finned tubes
International Journal of Heat and Mass Transfer, 2020-09, Vol. 158, No. 0, pp. 119849~ 0