Abstract
Single drop impact onto liquid films is simulated numerically. Surface tension and gravity are taken into account, whereas viscosity and compressibility are neglected. This permits recourse to a boundary-integral method, based on an integral equation for a scalar velocity potential. Calculations are performed for normal impacts resulting in axisymmetric flows. For times that are small compared to the characteristic time of impact 2R/w0 (R being the drop radius, w0 its initial velocity towards the liquid film), it is found that a disk-like jet forms at the neck between the drop and the pre-existing liquid film, if the impact Weber number is high enough. This jet can pinch off a torus-shaped liquid volume at its tip or reconnect with the pre-existing liquid film, thus entraining a torus-shaped bubble. In reality, both the torus-shaped bubble and liquid torus will decay according to Rayleigh's capillary instability, thus breaking the cylindrical symmetry. This mechanism of bubble entrainment differs from those described in literature. For times that are comparable to or larger than the characteristic time of impact, capillary waves on the film, or the well-known crowns, are obtained again according to whether the impact Weber number is low or high enough.
| Original language | English |
|---|---|
| Pages (from-to) | 229-254 |
| Number of pages | 26 |
| Journal | Journal of Fluid Mechanics |
| Volume | 385 |
| Publication status | Published - 1999 Apr 25 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Computational Mechanics
- Mechanics of Materials
- Physics and Astronomy(all)
- Condensed Matter Physics
Cite this
Single drop impact onto liquid films : Neck distortion, jetting, tiny bubble entrainment, and crown formation. / Weiss, Daniel A.; Yarin, Alexander.
In: Journal of Fluid Mechanics, Vol. 385, 25.04.1999, p. 229-254.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Single drop impact onto liquid films
T2 - Neck distortion, jetting, tiny bubble entrainment, and crown formation
AU - Weiss, Daniel A.
AU - Yarin, Alexander
PY - 1999/4/25
Y1 - 1999/4/25
N2 - Single drop impact onto liquid films is simulated numerically. Surface tension and gravity are taken into account, whereas viscosity and compressibility are neglected. This permits recourse to a boundary-integral method, based on an integral equation for a scalar velocity potential. Calculations are performed for normal impacts resulting in axisymmetric flows. For times that are small compared to the characteristic time of impact 2R/w0 (R being the drop radius, w0 its initial velocity towards the liquid film), it is found that a disk-like jet forms at the neck between the drop and the pre-existing liquid film, if the impact Weber number is high enough. This jet can pinch off a torus-shaped liquid volume at its tip or reconnect with the pre-existing liquid film, thus entraining a torus-shaped bubble. In reality, both the torus-shaped bubble and liquid torus will decay according to Rayleigh's capillary instability, thus breaking the cylindrical symmetry. This mechanism of bubble entrainment differs from those described in literature. For times that are comparable to or larger than the characteristic time of impact, capillary waves on the film, or the well-known crowns, are obtained again according to whether the impact Weber number is low or high enough.
AB - Single drop impact onto liquid films is simulated numerically. Surface tension and gravity are taken into account, whereas viscosity and compressibility are neglected. This permits recourse to a boundary-integral method, based on an integral equation for a scalar velocity potential. Calculations are performed for normal impacts resulting in axisymmetric flows. For times that are small compared to the characteristic time of impact 2R/w0 (R being the drop radius, w0 its initial velocity towards the liquid film), it is found that a disk-like jet forms at the neck between the drop and the pre-existing liquid film, if the impact Weber number is high enough. This jet can pinch off a torus-shaped liquid volume at its tip or reconnect with the pre-existing liquid film, thus entraining a torus-shaped bubble. In reality, both the torus-shaped bubble and liquid torus will decay according to Rayleigh's capillary instability, thus breaking the cylindrical symmetry. This mechanism of bubble entrainment differs from those described in literature. For times that are comparable to or larger than the characteristic time of impact, capillary waves on the film, or the well-known crowns, are obtained again according to whether the impact Weber number is low or high enough.
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M3 - Article
AN - SCOPUS:0032675304
VL - 385
SP - 229
EP - 254
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
SN - 0022-1120
ER -