Journal of Fluid Mechanics


Evolution of the ejecta sheet from the impact of a drop with a deep pool

L. V. Zhanga1, J. Toolea1 p1, K. Fezzaaa2 and R. D. Deegana1 c1

a1 Department of Physics, and Center for the Study of Complex Systems, University of Michigan, Ann Arbor, MI 48109, USA

a2 X-Ray Science Division, Argonne National Laboratory, Argonne, IL 60439, USA


We used optical and X-ray imaging to observe the formation of jets from the impact of a single drop with a deep layer of the same liquid. For high Reynolds number there are two distinct jets: the thin, fast and early-emerging ejecta; and the slow, thick and late-emerging lamella. For low Reynolds number the two jets merge into a single continuous jet, the structure of which is determined by the distinct contributions of the lamella and the ejecta. We measured the emergence time, position and speed of the ejecta sheet, and find that these scale as power laws with the impact speed and the viscosity. We identified the origin of secondary droplets with the breakup of the lamella and the ejecta jets, and show that the size of the droplets is not a good indicator of their origin.

(Received August 05 2011)

(Reviewed September 07 2011)

(Accepted September 13 2011)

(Online publication October 14 2011)

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    Key Words:

    • breakup/coalescence;
    • drops


    c1 Email address for correspondence:

    p1 Present address: Engineering Systems Division, MIT, Cambridge, MA 02139, USA