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Acoustic streaming has been widely used in microfluidics to manipulate various micro−/nano-objects. In this work, acoustic streaming activated by interdigital transducers (IDT) immersed in highly viscous oil is studied numerically and experimentally. In particular, we developed a modeling strategy termed the “slip velocity method” that enables a 3D simulation of surface acoustic wave microfluidics in a large domain (4 × 4 × 2 mm 3 ) and at a high frequency (23.9 MHz). The experimental and numerical results both show that on top of the oil, all the acoustic streamlines converge at two horizontal stagnation points above the two symmetric sides of the IDT. At these two stagnation points, water droplets floating on the oil can be trapped. Based on these characteristics of the acoustic streaming field, we designed a surface acoustic wave microfluidic device with an integrated IDT array fabricated on a 128° YX LiNbO 3 substrate to perform programmable, contactless droplet manipulation. By activating IDTs accordingly, the water droplets on the oil can be moved to the corresponding traps. With its excellent capability for manipulating droplets in a highly programmable, controllable manner, our surface acoustic wave microfluidic devices are valuable for on-chip contactless sample handling and chemical reactions.
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Flexible Piezoelectric Wave-Based Sensor: Numerical Analysis And Validation
The demand for acoustic wave-based devices has been rapidly increasing in the aerospace, chemical, and biological fields due to their versatility towards sensing measurands. This paper explores the characteristics and effectiveness of acoustic wave-based two-port sensors designed with bidirectional IDT electrodes placed in different configurations, such as surface mounted or embedded inside the substrate, through numerical and experimental analysis. The numerical study involves 3D modeling of the sensor design to investigate wave characteristics by utilizing time-domain, i.e., time delay and wave patterns, and frequency-domain analysis, i.e., scattering parameter study. The sensor made of polyvinylidene fluoride polymer is modeled to ensure the concordance between the theoretical and numerical results as well as a preliminary experimental result obtained from transparent piezoelectric films. The coupling of modes theoretical model is used to obtain the device’s frequency response by a transmission matrix cascading technique. These investigated results will stand as guidance and facilitate defining an approach that can predict the behavior of the sensor with a specific design under different operating environments and expand its viability towards multi-functional devices that are reliable and sensitive to intended measurands.
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- Award ID(s):
- 2018853
- PAR ID:
- 10476225
- Publisher / Repository:
- American Society of Mechanical Engineers
- Date Published:
- ISBN:
- 978-0-7918-8627-4
- Format(s):
- Medium: X
- Location:
- Dearborn, Michigan, USA
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Conference Paper:
- https://doi.org/10.1115/SMASIS2022-91069
