Abstract
Viscoplastic fluids, also known as yield-stress fluids, can stick and accumulate where they impact. Here we experimentally study conditions for open surfaces to be impermeable to impacting yield-stress fluid drops, and the dynamic conditions for these drops to permeate and coat internal aspects of a complex topography. We experimentally study drops of model yield stress fluids (Carbopol microgel particles in water) impacting open solid meshes (rigid surfaces with small, evenly spaced openings). High speed video reveals dynamics across a range of behavior, from 0% to 100% transmittance, by varying drop size, impact velocity, mesh geometry, and rheological material properties. When inertial stresses are sufficiently high compared to the yield stress, a drop can pass through a mesh, breaking into smaller fluid particles with varying shapes, sizes, and velocities in the process. In contrast, when inertial stresses are sufficiently low compared to the yield stress, a drop can stick to the mesh as though it were a solid surface, inhibited from passing through the holes by the yield stress. Layers of multiple meshes are also examined, demonstrating a range of behaviors and the ability to coat internal aspects of complex topography. Dimensional analysis is performed to characterize material transmittance and velocity of transmitted droplets as a function of dimensionless input parameters. Behavior is found to be well governed by the ratio of inertial stress to the sum of yield and viscous stresses.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 107-114 |
| Number of pages | 8 |
| Journal | Journal of Non-Newtonian Fluid Mechanics |
| Volume | 238 |
| DOIs | |
| State | Published - Dec 1 2016 |
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Keywords
- Complex topography
- Drop impact
- Viscoplastic
- Yield-stress fluid
ASJC Scopus subject areas
- Chemical Engineering(all)
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering
- Applied Mathematics
Cite this
Impacts of yield-stress fluid drops on permeable mesh substrates. / Blackwell, Brendan C.; Nadhan, Athrey E.; Ewoldt, Randy H.
In: Journal of Non-Newtonian Fluid Mechanics, Vol. 238, 01.12.2016, p. 107-114.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Impacts of yield-stress fluid drops on permeable mesh substrates
AU - Blackwell, Brendan C.
AU - Nadhan, Athrey E.
AU - Ewoldt, Randy H
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Viscoplastic fluids, also known as yield-stress fluids, can stick and accumulate where they impact. Here we experimentally study conditions for open surfaces to be impermeable to impacting yield-stress fluid drops, and the dynamic conditions for these drops to permeate and coat internal aspects of a complex topography. We experimentally study drops of model yield stress fluids (Carbopol microgel particles in water) impacting open solid meshes (rigid surfaces with small, evenly spaced openings). High speed video reveals dynamics across a range of behavior, from 0% to 100% transmittance, by varying drop size, impact velocity, mesh geometry, and rheological material properties. When inertial stresses are sufficiently high compared to the yield stress, a drop can pass through a mesh, breaking into smaller fluid particles with varying shapes, sizes, and velocities in the process. In contrast, when inertial stresses are sufficiently low compared to the yield stress, a drop can stick to the mesh as though it were a solid surface, inhibited from passing through the holes by the yield stress. Layers of multiple meshes are also examined, demonstrating a range of behaviors and the ability to coat internal aspects of complex topography. Dimensional analysis is performed to characterize material transmittance and velocity of transmitted droplets as a function of dimensionless input parameters. Behavior is found to be well governed by the ratio of inertial stress to the sum of yield and viscous stresses.
AB - Viscoplastic fluids, also known as yield-stress fluids, can stick and accumulate where they impact. Here we experimentally study conditions for open surfaces to be impermeable to impacting yield-stress fluid drops, and the dynamic conditions for these drops to permeate and coat internal aspects of a complex topography. We experimentally study drops of model yield stress fluids (Carbopol microgel particles in water) impacting open solid meshes (rigid surfaces with small, evenly spaced openings). High speed video reveals dynamics across a range of behavior, from 0% to 100% transmittance, by varying drop size, impact velocity, mesh geometry, and rheological material properties. When inertial stresses are sufficiently high compared to the yield stress, a drop can pass through a mesh, breaking into smaller fluid particles with varying shapes, sizes, and velocities in the process. In contrast, when inertial stresses are sufficiently low compared to the yield stress, a drop can stick to the mesh as though it were a solid surface, inhibited from passing through the holes by the yield stress. Layers of multiple meshes are also examined, demonstrating a range of behaviors and the ability to coat internal aspects of complex topography. Dimensional analysis is performed to characterize material transmittance and velocity of transmitted droplets as a function of dimensionless input parameters. Behavior is found to be well governed by the ratio of inertial stress to the sum of yield and viscous stresses.
KW - Complex topography
KW - Drop impact
KW - Viscoplastic
KW - Yield-stress fluid
UR - http://www.scopus.com/inward/record.url?scp=84996995759&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84996995759&partnerID=8YFLogxK
U2 - 10.1016/j.jnnfm.2016.06.012
DO - 10.1016/j.jnnfm.2016.06.012
M3 - Article
VL - 238
SP - 107
EP - 114
JO - Journal of Non-Newtonian Fluid Mechanics
JF - Journal of Non-Newtonian Fluid Mechanics
SN - 0377-0257
ER -