Lateral motion of a solid with a heterogeneous wettability surface driven by impacting droplets

Abstract When a droplet impacts a solid with a heterogeneous wettability surface, the generated asymmetric forces can manipulate the droplet, and its counterforces can also actuate the solid in theory. In this study, a water droplet impacting a movable hydrophobic substrate, which is decorated with a hydrophilic stripe and restrained by two linear dampers, is studied numerically. After preliminarily checking the effects of the solid mass and damping coefficient of linear dampers, the dynamic mechanisms of solid motion are explored by analysing the variations in the lateral force and instantaneous displacement distance of the solid. After that, the effects of the impact parameters on the solid lateral motion are mainly investigated, including the initial droplet diameter, impact velocity and offset distance between the impact point and hydrophilic stripe. On this basis, the reciprocating solid motion under successive droplet impacts is studied, and periodic motion with different amplitudes can be realized under appropriate impact conditions. The obtained results can shed some fresh insight into the potential applications of droplet–solid interactions, which are valuable for the collection and utilization of energy from natural environments.

[1]  Jie Wu,et al.  Scaling laws for the droplet rebound with lateral motion after impacting on heterogeneous surfaces , 2021, International Journal of Multiphase Flow.

[2]  Yanlin Song,et al.  Breaking the symmetry to suppress the Plateau–Rayleigh instability and optimize hydropower utilization , 2021, Nature Communications.

[3]  R. Kurose,et al.  Directional migration of an impinging droplet on a surface with wettability difference , 2020 .

[4]  Jie Wu,et al.  Lateral motion of a droplet impacting on a wettability-patterned surface: numerical and theoretical studies. , 2020, Soft matter.

[5]  D. Ingham,et al.  Analysis and prediction of the gas-liquid interfacial area for droplets impact on solid surfaces , 2020, Applied Thermal Engineering.

[6]  C. Megaridis,et al.  Numerical simulation of droplet impact on wettability-patterned surfaces , 2020, Physical Review Fluids.

[7]  D. Wen,et al.  Directional transportation of impacting droplets on wettability-controlled surfaces. , 2020, Langmuir : the ACS journal of surfaces and colloids.

[8]  Patricia B. Weisensee,et al.  Dynamic wetting and heat transfer during droplet impact on bi-phobic wettability-patterned surfaces , 2020, Physics of Fluids.

[9]  Jie Wu,et al.  An improved diffuse interface method for three‐dimensional multiphase flows with complex interface deformation , 2020, International Journal for Numerical Methods in Fluids.

[10]  Zhong Lin Wang,et al.  A droplet-based electricity generator with high instantaneous power density , 2020, Nature.

[11]  Yanlin Song,et al.  Steerable Droplet Bouncing for Precise Materials Transportation , 2019, Advanced Materials Interfaces.

[12]  J. Min,et al.  Maximum spreading of droplets impacting spherical surfaces , 2019, Physics of Fluids.

[13]  J. Min,et al.  Spreading of droplets impacting different wettable surfaces at a Weber number close to zero , 2019, Chemical Engineering Science.

[14]  Kui Yao,et al.  Water droplet impact energy harvesting with P(VDF-TrFE) piezoelectric cantilevers on stainless steel substrates , 2019, Smart Materials and Structures.

[15]  Qiang Yang,et al.  Spontaneous droplets gyrating via asymmetric self-splitting on heterogeneous surfaces , 2019, Nature Communications.

[16]  Andreas Mark,et al.  An immersed boundary based dynamic contact angle framework for handling complex surfaces of mixed wettabilities , 2018, International Journal of Multiphase Flow.

[17]  X. Ren,et al.  Dynamic effects and adhesion of water droplet impact on hydrophobic surfaces: bouncing or sticking. , 2017, Nanoscale.

[18]  W. King,et al.  Water droplet impact on elastic superhydrophobic surfaces , 2016, Scientific Reports.

[19]  Sigurdur T. Thoroddsen,et al.  Drop Impact on a Solid Surface , 2016 .

[20]  Baowei Song,et al.  Selectively splitting a droplet using superhydrophobic stripes on hydrophilic surfaces. , 2015, Physical chemistry chemical physics : PCCP.

[21]  Claire J. Carmalt,et al.  Robust self-cleaning surfaces that function when exposed to either air or oil , 2015, Science.

[22]  C. Megaridis,et al.  Morphing and vectoring impacting droplets by means of wettability-engineered surfaces , 2014, Scientific Reports.

[23]  Lei Jiang,et al.  Bio-inspired strategies for anti-icing. , 2014, ACS nano.

[24]  Gregory D. Bixler,et al.  Rice- and butterfly-wing effect inspired self-cleaning and low drag micro/nanopatterned surfaces in water, oil, and air flow. , 2014, Nanoscale.

[25]  D. Sivakumar,et al.  Impact of water drops onto the junction of a hydrophobic texture and a hydrophilic smooth surface , 2010 .

[26]  Chang Shu,et al.  Diffuse interface model for incompressible two-phase flows with large density ratios , 2007, J. Comput. Phys..

[27]  Junseok Kim,et al.  A continuous surface tension force formulation for diffuse-interface models , 2005 .

[28]  J. Waals.  The thermodynamic theory of capillarity under the hypothesis of a continuous variation of density , 1979 .

[29]  R. Hoffman.  A study of the advancing interface. I. Interface shape in liquid—gas systems , 1975 .

[30]  Hrvoje Jasak,et al.  Error analysis and estimation for the finite volume method with applications to fluid flows , 1996 .

[31]  O. Voinov.  Hydrodynamics of wetting , 1976 .