TY - JOUR
T1 - Impact on floating thin elastic sheets
T2 - A mathematical model
AU - O'Kiely, Doireann
AU - Box, Finn
AU - Kodio, Ousmane
AU - Whiteley, Jonathan
AU - Vella, Dominic
N1 - Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/1
Y1 - 2020/1
N2 - We investigate impact of a sphere onto a floating elastic sheet and the resulting formation and evolution of wrinkles in the sheet. Following impact, we observe a radially propagating wave, beyond which the sheet remains approximately planar but is decorated by a series of radial wrinkles whose wavelength grows in time. We develop a mathematical model to describe these phenomena by exploiting the asymptotic limit in which the bending stiffness is small compared to stresses in the sheet. The results of this analysis show that, at a time t after impact, the transverse wave is located at a radial distance r∼t1/2 from the impactor, in contrast to the classic r∼t2/3 scaling observed for capillary-inertia ripples produced by dropping a stone into a pond. We describe the shape of this wave, starting from the simplest case of a point impactor, but subsequently addressing a finite-radius spherical impactor, contrasting this case with the classic Wagner theory of impact. We show also that the coarsening of wrinkles in the flat portion of the sheet is controlled by the inertia of the underlying liquid: short-wavelength, small-amplitude wrinkles form at early times since they accommodate the geometrically imposed compression without significantly displacing the underlying liquid. As time progresses, the liquid accelerates and the wrinkles grow larger and coarsen. We explain this coarsening quantitatively using numerical simulations and scaling arguments, and we compare our predictions with experimental data.
AB - We investigate impact of a sphere onto a floating elastic sheet and the resulting formation and evolution of wrinkles in the sheet. Following impact, we observe a radially propagating wave, beyond which the sheet remains approximately planar but is decorated by a series of radial wrinkles whose wavelength grows in time. We develop a mathematical model to describe these phenomena by exploiting the asymptotic limit in which the bending stiffness is small compared to stresses in the sheet. The results of this analysis show that, at a time t after impact, the transverse wave is located at a radial distance r∼t1/2 from the impactor, in contrast to the classic r∼t2/3 scaling observed for capillary-inertia ripples produced by dropping a stone into a pond. We describe the shape of this wave, starting from the simplest case of a point impactor, but subsequently addressing a finite-radius spherical impactor, contrasting this case with the classic Wagner theory of impact. We show also that the coarsening of wrinkles in the flat portion of the sheet is controlled by the inertia of the underlying liquid: short-wavelength, small-amplitude wrinkles form at early times since they accommodate the geometrically imposed compression without significantly displacing the underlying liquid. As time progresses, the liquid accelerates and the wrinkles grow larger and coarsen. We explain this coarsening quantitatively using numerical simulations and scaling arguments, and we compare our predictions with experimental data.
UR - http://www.scopus.com/inward/record.url?scp=85084495144&partnerID=8YFLogxK
U2 - 10.1103/PhysRevFluids.5.014003
DO - 10.1103/PhysRevFluids.5.014003
M3 - Article
AN - SCOPUS:85084495144
SN - 2469-990X
VL - 5
SP - 014003-
JO - Physical Review Fluids
JF - Physical Review Fluids
IS - 1
M1 - 014003
ER -