Impacts of yield-stress fluid drops on permeable mesh substrates

Brendan C. Blackwell, Athrey E. Nadhan, Randy H Ewoldt

Research output: Contribution to journalArticle

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 languageEnglish (US)
Pages (from-to)107-114
Number of pages8
JournalJournal of Non-Newtonian Fluid Mechanics
Volume238
DOIs
StatePublished - Dec 1 2016

Fingerprint

Yield Stress
Yield stress
mesh
Substrate
Mesh
Fluid
Fluids
fluids
Substrates
Transmittance
Topography
Viscoplastic Fluid
Internal
Dimensional Analysis
Accumulate
transmittance
topography
Dimensionless
Droplet
Material Properties

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 journalArticle

Blackwell, Brendan C. ; Nadhan, Athrey E. ; Ewoldt, Randy H. / Impacts of yield-stress fluid drops on permeable mesh substrates. In: Journal of Non-Newtonian Fluid Mechanics. 2016 ; Vol. 238. pp. 107-114.
@article{8561a82c6fa34967b5cfdb013091374a,
title = "Impacts of yield-stress fluid drops on permeable mesh substrates",
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.",
keywords = "Complex topography, Drop impact, Viscoplastic, Yield-stress fluid",
author = "Blackwell, {Brendan C.} and Nadhan, {Athrey E.} and Ewoldt, {Randy H}",
year = "2016",
month = "12",
day = "1",
doi = "10.1016/j.jnnfm.2016.06.012",
language = "English (US)",
volume = "238",
pages = "107--114",
journal = "Journal of Non-Newtonian Fluid Mechanics",
issn = "0377-0257",
publisher = "Elsevier",

}

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 -