On the use of refractive-index-matched hydrogel for fluid velocity measurement within and around geometrically complex solid obstructions

Weitzman, Joel; Samuel, Lianna C.; Craig, Anna; Zeller, Robert B.; Monismith, Stephen G.; Koseff, Jeffrey R.

doi:10.1007/s00348-014-1862-x

Cited by 24 publications

(22 citation statements)

References 31 publications

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“…Data processing schemes like the one described above are unable to overcome the fundamental challenge of data paucity. For that, we have begun a transition toward data collection via particle image velocimetry, an approach that yields far richer velocity field information (Weitzman et al ; Zeller et al ; Zeller et al). This will allow us to characterize the horizontal variability of flow statistics and develop new methods for interpreting sparse measurements…”

Section: Discussionmentioning

confidence: 99%

The attenuation of current‐ and wave‐driven flow within submerged multispecific vegetative canopies

Weitzman

Zeller

Thomas

et al. 2015

Limnology & Oceanography

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Historically, submerged vegetative canopies have either been reported as or modeled after unispecific examples—communities comprised of only a single vegetative species or element type. Field surveys of a shallow Florida Bay seagrass meadow highlighted a more diverse benthic landscape. Although dominated by Thalassia testudinum, the communities were distinctly multispecific, composed of a mixture of both plant and algal species. Strap‐like seagrass elements defined the upper portion of these canopies (the upperstory) while broad‐bodied algal species were found concentrated close to the bed (the understory). To predict the hydrodynamic implications of this dual‐story canopy structure, we derived a new canopy flow attenuation model, formulated to account for vertical canopy heterogeneities like those seen at our field site. The model was validated through a series of laboratory experiments: multispecific canopy mimics were installed in a current‐wave flume and exposed to a range of unidirectional and oscillatory flows. Mean and fluctuating velocity was measured above and within each canopy to determine vegetation‐induced flow attenuation. Velocities near the bed were markedly reduced through the addition of understory elements, results that were consistent with model predictions. These findings suggest that accurate prediction of flow‐regulated processes like sediment transport and propagule dissemination depends on a thorough accounting of community composition. These properties are also expected to change in response to seasonal variability and episodic environmental stresses.

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Section: Discussionmentioning

confidence: 99%

The attenuation of current‐ and wave‐driven flow within submerged multispecific vegetative canopies

Weitzman

Zeller

Thomas

et al. 2015

Limnology & Oceanography

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“…The most common hydrogels include those based on polyacrylamide or agarose (Byron and Variano 2013). Weitzman et al (2014) explored the use of copolymers of polyacrylamide and sodium acrylate in creating hydrogels that were RI matched to water while being readily available at low cost and easily moulded. In another successful application, hydrogel spheres and water were also RI matched by Kang et al (2010) to perform visualization experiments showing the invasion drainage of porous media with density-matched immiscible liquids.…”

Section: Custom Polymers Resins and Hydrogelsmentioning

confidence: 99%

A review of solid–fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid–liquid and multiphase solid–liquid flows

2017

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Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid–liquid and solid–liquid–liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid–liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330–1.620 and 1.251–1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid–liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity

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“…The flow cell was packed with hydrogel grains (Figures and a). We followed the procedure of Weitzman et al () and Menter () to create hydrogel slabs from sodium polyacrylate‐co‐polyacrylamide hydrogel and deionized water. The resulting hydrogel slabs had a 99.02% water content by mass (and 0.98% of polymer) and a RI of 1.3327.…”

Section: Methodsmentioning

confidence: 99%

“…However, they could not apply RIM‐PIV with fresh water because of the prohibitive differences of their refractive indexes (Nafion RI = 1.35 and fresh water RI = 1.333). Hydrogel has a RI that matches that of fresh water, but studies on the use of the RIM‐PIV method with hydrogel have so far been limited to the visualization of flow within a staggered array of cylinders (Weitzman, Samuel, Craig, Zeller, & Monismith, and references herein cited) and the interaction of red blood cells (Rahgozar, Rosi, Kaucky, Walker, & Rival, ).…”

Section: Introductionmentioning

confidence: 99%

Seeing through porous media: An experimental study for unveiling interstitial flows

Rubol

Tonina

Vincent

et al. 2018

Hydrological Processes

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We describe a novel inexpensive method, utilizing particle image velocimetry (PIV) and refractive index‐matching (RIM) for visualizing and quantifying the flow field within bio‐amended porous media. To date, this technique has been limited to idealized particles, whose refractive index does not match that of fresh water and thus requires specialized and often toxic or hazardous fluids. Here, we use irregularly shaped grains made of hydrogel as the solid matrix and water as the fluid. The advantage of using water is that it provides, for the first time, the opportunity to study both hydraulic and biological processes, which typically occur in soils and streambeds. By using RIM coupled with PIV (RIM‐PIV), we measured the interstitial flow field within a cell packed with granular material consisting of hydrogel grains in a size range of 1–8 mm, both in the presence and in the absence of Sinorhizobium meliloti bacteria (strain Rm8530). We also performed experiments with fluorescent tracer (fluorescein) and fluorescent microbes (Shewanella GPF MR‐1) to test the capability of visualizing solute transport and microbial movements. Results showed that the RIM‐PIV can measure the flow field for both biofilm‐free and biofilm‐covered hydrogel grains. The fluorescent tracer injection showed the ability to visualize both physical (concave surfaces and eddies) and biological (biofilms) transient storage zones, whereas the fluorescent microbe treatment showed the ability to track microbial movements within fluids. We conclude that the proposed methodology is a promising tool to visualize and quantify biofilm attachment, growth, and detachment in a system closer to natural conditions than a 2D flow cell experiment.

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On the use of refractive-index-matched hydrogel for fluid velocity measurement within and around geometrically complex solid obstructions

Cited by 24 publications

References 31 publications

The attenuation of current‐ and wave‐driven flow within submerged multispecific vegetative canopies

The attenuation of current‐ and wave‐driven flow within submerged multispecific vegetative canopies

A review of solid–fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid–liquid and multiphase solid–liquid flows

Seeing through porous media: An experimental study for unveiling interstitial flows

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