TY - JOUR

T1 - Numerical contact line behavior prediction for droplet-wall impact by the modified Hoffman-function-based dynamic contact angle model

AU - Vozhakov, I. S.

AU - Misyura, S. Y.

AU - Shain, A. M.

AU - Mullyadzhanov, R. I.

AU - Piskunov, M. V.

AU - Strizhak, P. A.

PY - 2025/1

Y1 - 2025/1

N2 - The droplet-wall impact phenomenon is observed in numerous applications such as spray cooling, coatings, wetting, and inkjet printing. To date, there are still unresolved issues related to the effect of wettability and hysteresis on droplet spreading along a wall and rim fingering. This research deals with the effects of dynamic and static contact angles on droplet spreading evolution, as well as with droplet rim fingering characterization. Experiments and direct numerical simulations are performed in a wide range of Weber numbers (We = 1–375). At high We numbers, the droplet rim loses stability and begins to deform, forming fingers. The critical disturbances resulting in the formation of fingers occur in times of around 1 ms, which are significantly smaller than those typical of maximum droplet spreading. Moreover, a certain shape of the droplet meniscus is shown to be necessary for the growth of fingers. When the contact line receding takes place, the contact angle depends only on the initial contact line acceleration. Considering the contact angle hysteresis and its dependence on We ensures a better agreement with experimental data during the droplet advancing-to-receding transition and the receding phase.

AB - The droplet-wall impact phenomenon is observed in numerous applications such as spray cooling, coatings, wetting, and inkjet printing. To date, there are still unresolved issues related to the effect of wettability and hysteresis on droplet spreading along a wall and rim fingering. This research deals with the effects of dynamic and static contact angles on droplet spreading evolution, as well as with droplet rim fingering characterization. Experiments and direct numerical simulations are performed in a wide range of Weber numbers (We = 1–375). At high We numbers, the droplet rim loses stability and begins to deform, forming fingers. The critical disturbances resulting in the formation of fingers occur in times of around 1 ms, which are significantly smaller than those typical of maximum droplet spreading. Moreover, a certain shape of the droplet meniscus is shown to be necessary for the growth of fingers. When the contact line receding takes place, the contact angle depends only on the initial contact line acceleration. Considering the contact angle hysteresis and its dependence on We ensures a better agreement with experimental data during the droplet advancing-to-receding transition and the receding phase.

KW - Contact angle hysteresis

KW - Droplet contact angle

KW - Droplet contact line

KW - Droplet-wall impact

KW - Fingering

UR - https://www.mendeley.com/catalogue/27ec9efd-924b-33bc-aa2a-338838046b0c/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85209590689&origin=inward&txGid=a5a9e4bbacd43f675ed4e518b8d9fc52

U2 - 10.1016/j.icheatmasstransfer.2024.108372

DO - 10.1016/j.icheatmasstransfer.2024.108372

M3 - Article

VL - 160

JO - International Communications in Heat and Mass Transfer

JF - International Communications in Heat and Mass Transfer

SN - 0735-1933

M1 - 108372

ER -