Zhang L.-ZWang Y.-BGao S.-RLin D.-JYang Y.-RWang X.-DLee D.-J.DUU-JONG LEE2022-03-222022-03-22202118761070https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111309159&doi=10.1016%2fj.jtice.2021.07.012&partnerID=40&md5=94f792cfa9fec51e276bdd78d1dc8e07https://scholars.lib.ntu.edu.tw/handle/123456789/598160Background: Droplet impact on a superhydrophobic cylinder differs from that on a flat surface. After bouncing, once re-touch takes place, the contact time τc would increase, which is unfavorable for some applications. The increased τc may strongly depend on the Weber number and radius ratio, R*, of cylinder to droplet. Methods: The impact is investigated via lattice Boltzmann method simulations. The particular emphasis is placed on re-touch rebound patterns and τc. Significant findings: Rebound patterns and τc both strongly depend on a combined parameter, α=We/R*, characterizing the asymmetry of droplet spreading and retraction. As α increases, upward rebound and stretched breakup take place sequentially for the first bouncing, whereas rebound patterns change as intact re-touch rebound and separate re-touch rebound for the second bouncing. Increasing α enhances the asymmetry, which promotes the first rebound, thereby reducing τc regardless of rebound patterns. The enhanced asymmetry also accelerates rebound and thus reduces τc in the separate re-touch rebound regime, whereas it hinders rebound, leading to a significantly increased τc. The power-law correlations of τc vs α are developed for the first and second bouncing. Besides, a method is proposed to suppress or prevent the re-touch, which is proven to effectively reduce τc. ? 2021 Taiwan Institute of Chemical EngineersContact timeCylinderDropletImpactRe-touchCylinders (shapes)SuperhydrophobicityCombined parameterDroplet impactDroplet spreadingFlat surfacesLattice Boltzmann methodPower-law correlationsRadius ratioWeber numbersDrop formation[SDGs]SDG6journal article10.1016/j.jtice.2021.07.0122-s2.0-85111309159