title: Symmetry breaking in drop bouncing on curved surfaces.
abstract: The impact of liquid drops on solid surfaces is ubiquitous in nature, and of practical importance in many industrial processes. A drop hitting a flat surface retains a circular symmetry throughout the impact process. Here we show that a drop impinging on Echevaria leaves exhibits asymmetric bouncing dynamics with distinct spreading and retraction along two perpendicular directions. This is a direct consequence of the cylindrical leaves that have a convex/concave architecture of size comparable to the drop. Systematic experimental investigations on mimetic surfaces and lattice Boltzmann simulations reveal that this novel phenomenon results from an asymmetric momentum and mass distribution that allows for preferential fluid pumping around the drop rim. The asymmetry of the bouncing leads to ∼40% reduction in contact time.
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China.|Key Laboratory for Precision &Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
authors.forename: Yahua
authors.identifier: http://orcid.org/0000-0003-4671-698X
authors.initials: Y
authors.lastname: Liu
authors.affiliation: The Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Andrew
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: The Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, Oxford OX1 3NP, UK.
authors.forename: Julia M
authors.initials: JM
authors.lastname: Yeomans
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China.|Shenzhen Research Institute of City University of Hong Kong, Shenzhen 518057, China.
authors.forename: Zuankai
authors.initials: Z
authors.lastname: Wang