FSVPy: A python-based package for fluorescent streak velocimetry (FSV)

Han Lin, Brendan C. Blackwell, Connor C. Call, Shanliangzi Liu, Claire Liu, Michelle M. Driscoll*, Jeffrey J. Richards*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Predictive constitutive equations that connect easy-to-measure transport properties (e.g., viscosity and conductivity) with system performance variables (e.g., power consumption and efficiency) are needed to design advanced thermal and electrical systems. In this work, we explore the use of fluorescent particle-streak analysis to directly measure the local velocity field of a pressure-driven flow, introducing a new Python package (FSVPy) to perform the analysis. Fluorescent streak velocimetry combines high-speed imaging with highly fluorescent particles to produce images that contain fluorescent streaks, whose length and intensity can be related to the local flow velocity. By capturing images throughout the sample volume, the three-dimensional velocity field can be quantified and reconstructed. We demonstrate this technique by characterizing the channel flow profiles of several non-Newtonian fluids: micellar Cetylpyridinium Chloride solution, Carbopol 940, and Polyethylene Glycol. We then explore more complex flows, where significant acceleration is created due to microscale features encountered within the flow. We demonstrate the ability of FSVPy to process streaks of various shapes and use the variable intensity along the streak to extract position-specific velocity measurements from individual images. Thus, we demonstrate that FSVPy is a flexible tool that can be used to extract local velocimetry measurements from a wide variety of fluids and flow conditions.

Original languageEnglish (US)
Pages (from-to)197-206
Number of pages10
JournalJournal of Rheology
Volume67
Issue number1
DOIs
StatePublished - Jan 1 2023

Funding

The authors appreciate the help from Professor John A. Rogers of Northwestern University on the fabrication of complex microchannels. We also acknowledge helpful discussions regarding graph theory algorithms with Istvan Kovacs. Han Lin was partially funded by the Department of Energy (DOE) Basic Energy Science Program (No. DE-SC0022119). Han Lin and Brendan C. Blackwell were partially funded by Leslie and Mac McQuown through the Center for Engineering Sustainability and Resilience at Northwestern. This work made use of the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF under No. ECCS-2025633), the Northwestern's International Institute for Nanotechnology, and Northwestern’s MRSEC program (NSF under No. DMR-1720139). Codes and tutorials can be found at https://github.com/mmdriscoll/FSVPy .

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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