TY - JOUR
T1 - Simulations of surface acoustic wave interactions on a sessile droplet using a three-dimensional multiphase lattice Boltzmann model
AU - Burnside, Stephen B.
AU - Pasieczynski, Kamil
AU - Zarareh, Amin
AU - Mehmood, Mubbashar
AU - Fu, Yong Qing
AU - Chen, Baixin
N1 - Funding Information:
S.B.B. was supported by EPSRC Doctoral Training Partnerships. The authors also acknowledge the financial support from EPSRC Grant No. EP/P018998/1 and Special Interests Group of Acoustofluidics under the EPSRC-funded UK Fluidic Network (Grant No. EP/N032861/1).
Publisher Copyright:
© 2021 American Physical Society.
PY - 2021/10/1
Y1 - 2021/10/1
N2 - This study reports the development of a three-dimensional numerical model for acoustic interactions with a microscale sessile droplet under surface acoustic wave (SAW) excitation using the lattice Boltzmann method (LBM). We first validate the model before SAW interactions are added. The results demonstrate good agreement with the analytical results for thermodynamic consistency, Laplace law, static contact angle on a flat surface, and droplet oscillation. We then investigate SAW interactions on the droplet, with resonant frequencies ranging 61.7-250.1 MHz. According to our findings, an increase in wave amplitude elicits an increase in streaming velocity inside the droplet, causing internal mixing, and further increase in wave amplitude leads to pumping and jetting. The boundaries of wave amplitude at various resonant frequencies are predicted for mixing, pumping, and jetting modes. The modeling predictions on the roles of forces (SAW, interfacial tension, inertia, and viscosity) on the dynamics of mixing, pumping, and jetting of a droplet are in good agreement with observations and experimental data. The model is further applied to investigate the effects of SAW substrate surface wettability, viscosity ratio, and interfacial tension on SAW actuation onto the droplet. This work demonstrates the capability of the LBM in the investigation of acoustic wave interactions between SAW and a liquid medium.
AB - This study reports the development of a three-dimensional numerical model for acoustic interactions with a microscale sessile droplet under surface acoustic wave (SAW) excitation using the lattice Boltzmann method (LBM). We first validate the model before SAW interactions are added. The results demonstrate good agreement with the analytical results for thermodynamic consistency, Laplace law, static contact angle on a flat surface, and droplet oscillation. We then investigate SAW interactions on the droplet, with resonant frequencies ranging 61.7-250.1 MHz. According to our findings, an increase in wave amplitude elicits an increase in streaming velocity inside the droplet, causing internal mixing, and further increase in wave amplitude leads to pumping and jetting. The boundaries of wave amplitude at various resonant frequencies are predicted for mixing, pumping, and jetting modes. The modeling predictions on the roles of forces (SAW, interfacial tension, inertia, and viscosity) on the dynamics of mixing, pumping, and jetting of a droplet are in good agreement with observations and experimental data. The model is further applied to investigate the effects of SAW substrate surface wettability, viscosity ratio, and interfacial tension on SAW actuation onto the droplet. This work demonstrates the capability of the LBM in the investigation of acoustic wave interactions between SAW and a liquid medium.
UR - http://www.scopus.com/inward/record.url?scp=85117197849&partnerID=8YFLogxK
U2 - 10.1103/PhysRevE.104.045301
DO - 10.1103/PhysRevE.104.045301
M3 - Article
C2 - 34781429
AN - SCOPUS:85117197849
VL - 104
JO - Physical Review E
JF - Physical Review E
SN - 2470-0045
IS - 4
M1 - 045301
ER -