TY - JOUR
T1 - Air-cushioning effect and Kelvin-Helmholtz instability before the slamming of a disk on water
AU - Jain, Utkarsh
AU - Gauthier, Anaïs
AU - Lohse, Detlef
AU - Meer, Devaraj van der
PY - 2021/4/29
Y1 - 2021/4/29
N2 - The macroscopic dynamics of a droplet impacting a solid is crucially determined by the intricate air dynamics occurring at the vanishingly small length scale between droplet and substrate prior to direct contact. Here we investigate the inverse problem, namely, the role of air for the impact of a horizontal flat disk onto a liquid surface, and find an equally significant effect. Using an in-house experimental technique, we measure the free surface deflections just before impact, with a precision of a few micrometers. Whereas stagnation pressure pushes down the surface in the center, we observe a liftup under the edge of the disk, which sets in at a later stage, and which we show to be consistent with a Kelvin-Helmholtz instability of the water-air interface.
AB - The macroscopic dynamics of a droplet impacting a solid is crucially determined by the intricate air dynamics occurring at the vanishingly small length scale between droplet and substrate prior to direct contact. Here we investigate the inverse problem, namely, the role of air for the impact of a horizontal flat disk onto a liquid surface, and find an equally significant effect. Using an in-house experimental technique, we measure the free surface deflections just before impact, with a precision of a few micrometers. Whereas stagnation pressure pushes down the surface in the center, we observe a liftup under the edge of the disk, which sets in at a later stage, and which we show to be consistent with a Kelvin-Helmholtz instability of the water-air interface.
U2 - 10.1103/PhysRevFluids.6.L042001
DO - 10.1103/PhysRevFluids.6.L042001
M3 - Article
VL - 6
JO - Physical review fluids
JF - Physical review fluids
SN - 2469-990X
IS - 4
M1 - L042001
ER -