WU Xin, GAO Tieyu, GONG Jianying, et al. Wetting Characteristics of Droplet Migration Against Gravity on Inclined Surfaces under Ultrasonic Excitation[J]. Journal of Xi'an Jiaotong University,2026,60 (9):142-153. https://doi.org/10.7652/xjtuxb202609014.
DOI:
WU Xin, GAO Tieyu, GONG Jianying, et al. Wetting Characteristics of Droplet Migration Against Gravity on Inclined Surfaces under Ultrasonic Excitation[J]. Journal of Xi'an Jiaotong University,2026,60 (9):142-153. https://doi.org/10.7652/xjtuxb202609014.DOI:
Wetting Characteristics of Droplet Migration Against Gravity on Inclined Surfaces under Ultrasonic Excitation
To investigate the dynamic wetting behavior of droplets migrating against gravity on an inclined aluminum surface under 35 kHz ultrasonic excitation
the effects of droplet volume
ultrasonic vibration velocity
and surface inclination angle on the droplet diameter spreading ratio and contact angle hysteresis are quantitatively analyzed.The evolution of the wetting behavior during droplet migration against gravity on the inclined surface is revealed
and the synergistic relationship between microscopic wetting characteristics and macroscopic dynamic behavior is established.Furthermore
based on the force competition mechanism
a combined dimensionless number involving the acoustic Weber number and Bond number is constructed
and an empirical relationship for predicting the droplet dynamic response is established.The results show that droplet wettability is significantly enhanced by ultrasonic excitation
and migration against gravity is achieved on surfaces inclined at 30°
60°
90°
with a maximum displacement of approximately 5.04 mm.Under ultrasonic excitation
the droplet diameter spreading ratio exhibits a nonlinear evolution of “increase-peak-retraction-steady state”
with the maximum diameter spreading ratio ranging from 1.16 to 1.51 and mainly increasing with ultrasonic vibration velocity.In addition
gravity-induced wetting asymmetry is effectively weakened by ultrasonic vibration
and contact angle hysteresis is shifted from a gravity-dominated negative state to an acoustic-field-dominated positive state.The combined dimensionless number corresponding to the critical transition is 18.79.A theoretical and experimental basis for acousticfield-based droplet transport and surface wetting control is provided by this study.
Liu Xue,Lai Tianwei,Zhao Qi,et al.Experimental study on effect of parameter variation along confined flow path on frosting characteristics of vertical circular tube surface[J].Journal of Xi'an Jiaotong University, 2022,56(5):149-155.
Tan Haihui,Tao Tangfei,Xu Guanghua,et al.Ultrasonic defrosting theory and technology for finned-tube evaporator[J].Journal of Xi'an Jiaotong University, 2015,49(9):105-113.
Wu Xiaomin,Chu Fuqiang,Chen Yonggen.Theoretical analysis of droplets growth in early stage of frosting on hydrophobic surfaces[J].CIESC Journal,2015, 66(S1):60-64.
Ling Weihao,Wu Jingtao,Li Xuan,et al.Numerical prediction of frosting growth characteristics of microchannel louvered fin heat exchanger[J].Energy, 2023,283:128519.
Vocale P,Morini G L,Spiga M.Influence of outdoor air conditions on the air source heat pumps performance[J].Energy Procedia,2014,45:653-662.
Yeo L Y,Friend J R.Surface acoustic wave microfluidics[J].Annual Review of Fluid Mechanics,2014, 46:379-406.
Datta S,Sharma M,Das A K.Investigation of upward climbing motion of a droplet over an inclined surface using electrowetting[J].Industrial & Engineering Chemistry Research,2014,53(16):6685-6693.
Gao Anran,Li Tie,Liu Xiang,et al.Study on transportation behavior of droplet driven by thermal gradient[J].Journal of Test and Measurement Technolo gy,2010,24(5):377-380.
Seerha P P S,Kumar P,Das A K,et al.Proposition of stair climb of a drop using chemical wettability gradient[J].Physics of Fluids,2017,29(7):072103.
Chamakos N T,Karapetsas G,Papathanasiou A G.How asymmetric surfaces induce directional droplet motion[J].Colloids and Surfaces:A Physicochemical and Engineering Aspects,2016,511:180-189.
Luo Tao,Liu Sirui,Zhou Rui,et al.Contactless acoustic tweezer for droplet manipulation on superhydrophobic surfaces[J].Lab on a Chip,2023,23(18):3989-4001.
Brunet P,Baudoin M,Matar O B,et al.Droplet displacements and oscillations induced by ultrasonic surface acoustic waves:a quantitative study[J].Physical Review:E,2010,81(3):036315.
Wu Xin,Gong Jianying,Jin Long,et al.Study on the transportation characteristics of droplets on the aluminium surface under ultrasonic excitation[J].CIESC Journal,2023,74(S1):104-112.
Galleguillos-Silva R, Vargas-Hernández Y, GaeteGarretón L.Wettability of a surface subjected to high frequency mechanical vibrations[J].Ultrasonics Sonochemistry,2017,35(Part A):134-141.
Guo Jiaojiao,Chen Xiaopeng,Shui Langquan.Surface wave mechanism for directional motion of droplet on an obliquely vibrated substrate[J].Physics of Fluids, 2020,32(3):031701.
Trapuzzano M,Tej ada-Martínez A, Guldiken R, et al.Volume and Frequency-Independent spreading of droplets driven by ultrasonic surface vibration[J].Fluids,2020,5(1):18.
Scortesse J,Manceau J F,Bastien F.Displacement of droplets on a vibrating structure[J].Ultrasonics, 2002,40(1/2/3/4/5/6/7/8):349-353.
Fukaya T,Kondoh J.Experimental consideration of droplet manipulation mechanism using surface acoustic wave[J].Japanese Journal of Applied Physics,2015, 54(7S1):07HE06.
De Jong E,Wang Ye,Den Toonder J M J,et al.Climbing droplets driven by mechanowetting on transverse waves[J].Science Advances,2019,5(6):eaaw0914.
Sartori P,Quagliati D,Varagnolo S,et al.Drop motion induced by vertical vibrations[J].New Journal of Physics,2015,17(11):113017.
Li Dong,Chen Zhenqian,Shi Mingheng.Effect of ultrasound on frost formation on a cold flat surface in atmospheric air flow[J].Experimental Thermal and Fluid Science,2010,34(8):1247-1252.
Wang Dingyuan,Tao Tangfei,Xu Guanghua,et al.Experimental study on frosting suppression for a finned-tube evaporator using ultrasonic vibration[J].Experimental Thermal and Fluid Science,2012,36:1-11.
Amer M,Wang Chichuan.Experimental investigation on defrosting of a cold flat plate via ultrasonic vibration under natural convection[J].Applied Thermal Engineering,2020,179:115729.
Wu Xin,Gong Jianying,Gao Tieyu,et al.Experimental study on dynamic wetting behavior of liquid droplets on the aluminum surfaces excited by ultrasonic waves[J].Applied Thermal Engineering,2024, 248(Part A):123209.
Wu Xin,Gong Jianying,Jiang Zhen,et al.Droplet transport dynamics induced by ultrasonic vibration on horizontal metal surface[J].Physics of Fluids,2025, 37(7):072116.
Wu Xin,Gong Jianying,Wang Yutao,et al.Motion and rupture properties of droplets on inclined surfaces under ultrasonic excitation[J].International Journal of Heat and Mass Transfer ,2026,256(Part 3):128108.
Ren Zheng,Zhang Xingqun,Zhang Beile,et al.Experimental study on the frosting behavior of horizontal circular tube surface at -60℃[J].Journal of Xi'an Jiaotong University,2019,53(7):78-83.