Multilayer nano-particle image velocimetry

Haifeng Li, Reza Sadr, Minami Yoda

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Nano-particle image velocimetry (nPIV), based on evanescent-wave illumination of fluorescent colloidal tracers, measures the two velocity components parallel to the wall averaged over the first few hundred nanometers next to the wall. The intensity of the evanescent wave decays exponentially with z, or the distance normal to the wall. Illuminated tracers closer to the wall therefore have images that are brighter than those farther from the wall. This nonuniform illumination presents the possibility to extend the technique to "multilayer nPIV," where the two velocity components parallel to the wall can be estimated at different z-locations within the illuminated region. In this paper, the variation of tracer image intensity with distance from the wall was predicted using diffraction optics-based approaches. The predictions, which were validated by calibration experiments, show that particle image intensity decays exponentially with distance normal to the wall. The feasibility of multilayer nPIV was evaluated using artificial images of plane Couette flow that incorporate evanescent-wave illumination, hindered Brownian diffusion and image noise. Each image was divided into three sub-images based on tracer image intensity, and standard techniques were then used to extract temporally and spatially averaged velocities at three different z-locations. In these simulations, velocity data were obtained within 80 nm of the wall, a threefold improvement over previous measurements. The results demonstrate that multilayer nPIV is feasible if appropriate classification techniques are developed and used to separate tracer images into different layers.

Original languageEnglish
Pages (from-to)185-194
Number of pages10
JournalExperiments in Fluids
Volume41
Issue number2
DOIs
Publication statusPublished - Aug 2006
Externally publishedYes

Fingerprint

particle image velocimetry
Velocity measurement
Multilayers
Lighting
tracers
evanescent waves
illumination
Optics
Diffraction
Calibration
diffractive optics
Couette flow
decay
Experiments
predictions

ASJC Scopus subject areas

  • Computational Mechanics
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes

Cite this

Multilayer nano-particle image velocimetry. / Li, Haifeng; Sadr, Reza; Yoda, Minami.

In: Experiments in Fluids, Vol. 41, No. 2, 08.2006, p. 185-194.

Research output: Contribution to journalArticle

Li, Haifeng ; Sadr, Reza ; Yoda, Minami. / Multilayer nano-particle image velocimetry. In: Experiments in Fluids. 2006 ; Vol. 41, No. 2. pp. 185-194.
@article{5dc08b8c343d4ed9a948440df59cacd5,
title = "Multilayer nano-particle image velocimetry",
abstract = "Nano-particle image velocimetry (nPIV), based on evanescent-wave illumination of fluorescent colloidal tracers, measures the two velocity components parallel to the wall averaged over the first few hundred nanometers next to the wall. The intensity of the evanescent wave decays exponentially with z, or the distance normal to the wall. Illuminated tracers closer to the wall therefore have images that are brighter than those farther from the wall. This nonuniform illumination presents the possibility to extend the technique to {"}multilayer nPIV,{"} where the two velocity components parallel to the wall can be estimated at different z-locations within the illuminated region. In this paper, the variation of tracer image intensity with distance from the wall was predicted using diffraction optics-based approaches. The predictions, which were validated by calibration experiments, show that particle image intensity decays exponentially with distance normal to the wall. The feasibility of multilayer nPIV was evaluated using artificial images of plane Couette flow that incorporate evanescent-wave illumination, hindered Brownian diffusion and image noise. Each image was divided into three sub-images based on tracer image intensity, and standard techniques were then used to extract temporally and spatially averaged velocities at three different z-locations. In these simulations, velocity data were obtained within 80 nm of the wall, a threefold improvement over previous measurements. The results demonstrate that multilayer nPIV is feasible if appropriate classification techniques are developed and used to separate tracer images into different layers.",
author = "Haifeng Li and Reza Sadr and Minami Yoda",
year = "2006",
month = "8",
doi = "10.1007/s00348-006-0155-4",
language = "English",
volume = "41",
pages = "185--194",
journal = "Experiments in Fluids",
issn = "0723-4864",
publisher = "Springer Verlag",
number = "2",

}

TY - JOUR

T1 - Multilayer nano-particle image velocimetry

AU - Li, Haifeng

AU - Sadr, Reza

AU - Yoda, Minami

PY - 2006/8

Y1 - 2006/8

N2 - Nano-particle image velocimetry (nPIV), based on evanescent-wave illumination of fluorescent colloidal tracers, measures the two velocity components parallel to the wall averaged over the first few hundred nanometers next to the wall. The intensity of the evanescent wave decays exponentially with z, or the distance normal to the wall. Illuminated tracers closer to the wall therefore have images that are brighter than those farther from the wall. This nonuniform illumination presents the possibility to extend the technique to "multilayer nPIV," where the two velocity components parallel to the wall can be estimated at different z-locations within the illuminated region. In this paper, the variation of tracer image intensity with distance from the wall was predicted using diffraction optics-based approaches. The predictions, which were validated by calibration experiments, show that particle image intensity decays exponentially with distance normal to the wall. The feasibility of multilayer nPIV was evaluated using artificial images of plane Couette flow that incorporate evanescent-wave illumination, hindered Brownian diffusion and image noise. Each image was divided into three sub-images based on tracer image intensity, and standard techniques were then used to extract temporally and spatially averaged velocities at three different z-locations. In these simulations, velocity data were obtained within 80 nm of the wall, a threefold improvement over previous measurements. The results demonstrate that multilayer nPIV is feasible if appropriate classification techniques are developed and used to separate tracer images into different layers.

AB - Nano-particle image velocimetry (nPIV), based on evanescent-wave illumination of fluorescent colloidal tracers, measures the two velocity components parallel to the wall averaged over the first few hundred nanometers next to the wall. The intensity of the evanescent wave decays exponentially with z, or the distance normal to the wall. Illuminated tracers closer to the wall therefore have images that are brighter than those farther from the wall. This nonuniform illumination presents the possibility to extend the technique to "multilayer nPIV," where the two velocity components parallel to the wall can be estimated at different z-locations within the illuminated region. In this paper, the variation of tracer image intensity with distance from the wall was predicted using diffraction optics-based approaches. The predictions, which were validated by calibration experiments, show that particle image intensity decays exponentially with distance normal to the wall. The feasibility of multilayer nPIV was evaluated using artificial images of plane Couette flow that incorporate evanescent-wave illumination, hindered Brownian diffusion and image noise. Each image was divided into three sub-images based on tracer image intensity, and standard techniques were then used to extract temporally and spatially averaged velocities at three different z-locations. In these simulations, velocity data were obtained within 80 nm of the wall, a threefold improvement over previous measurements. The results demonstrate that multilayer nPIV is feasible if appropriate classification techniques are developed and used to separate tracer images into different layers.

UR - http://www.scopus.com/inward/record.url?scp=33746818364&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33746818364&partnerID=8YFLogxK

U2 - 10.1007/s00348-006-0155-4

DO - 10.1007/s00348-006-0155-4

M3 - Article

VL - 41

SP - 185

EP - 194

JO - Experiments in Fluids

JF - Experiments in Fluids

SN - 0723-4864

IS - 2

ER -