2008/09/25 by Stephan Gekle, José Manuel Gordillo, Devaraj van der Meer +1 · 141 citations
Engineering · Physics and Astronomy · #Classical mechanics #Flow (mathematics) #Fluid Dynamics Simulations and Interactions #Fluid Dynamics and Heat Transfer #Heat transfer #Impact crater #Jet (fluid) #Mechanics #Physics #Planetary Science and Exploration #Rotational symmetry #Stagnation point #physics.flu-dyn
paper · pdf · doi:10.1103/physrevlett.102.034502
published in Physical Review Letters 102(3), 034502 (American Physical Society)
arxiv created 2008/09/25 · openalex publication_date 2009/01/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A circular disc hitting a water surface creates an impact crater which after collapse leads to a vigorous jet. Upon impact an axisymmetric air cavity forms and eventually pinches off in a single point halfway down the cavity. Two fast sharp-pointed jets are observed shooting up- and downwards from the closure location, which by then has turned into a stagnation point surrounded by a locally hyperbolic flow pattern. This flow, however, is not the mechanism feeding the jets. Using high-speed imaging and numerical simulations we show that jetting is fed by the local flow around the base of the jet, which is forced by the colliding cavity walls. We show how the well-known theory of a collapsing void (using a line of sinks on the symmetry axis) can be continued beyond pinch-off to obtain a new and quantitative model for jet formation which agrees well with numerical and experimental data.