Flow in Curved Pipes

Controlling the shape of fluid streams is important across scales: from industrial processing to control of biomolecular interactions. Previous approaches to control fluid streams have focused mainly on creating chaotic flows to enhance mixing. Here we develop an approach to apply order using sequences of fluid transformations rather than enhancing chaos. We investigate the inertial flow deformations around a library of single cylindrical pillars within a microfluidic channel and assemble these net fluid transformations to engineer fluid streams. As these transformations provide a deterministic mapping of fluid elements from upstream to downstream of a pillar, we can sequentially arrange pillars to apply the associated nested maps and, therefore, create complex fluid structures without additional numerical simulation. To show the range of capabilities, we present sequences that sculpt the cross-sectional shape of a stream into complex geometries, move and split a fluid stream, perform solution exchange and achieve particle separation. A general strategy to engineer fluid streams into a broad class of defined configurations in which the complexity of the nonlinear equations of fluid motion are abstracted from the user is a first step to programming streams of any desired shape, which would be useful for biological, chemical and materials automation.

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“…1b). The phenomenon has features in common with the secondary flow created in curved channels with finite inertia (Dean flow) 1,19,20 .…”

Section: Resultsmentioning

confidence: 97%

Engineering fluid flow using sequenced microstructures

et al. 2013

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“…Experimental, theoretical, and numerical studies have been carried out to study laminar flow in idealised geometries, such as flow around bends of constant curvature (e.g., Refs. [8][9][10][11][12][13][14][15][16][17][18][19] or helical tubes of constant curvature and torsion (e.g., Refs. 15 and 20-23).…”

Section: Introductionmentioning

confidence: 99%

“…In some cases, it is possible to reduce the set of parameters to a small number, a classic example of this being Dean flow. 10,11,15 However, the relevance of these solutions to flow in real blood vessels is not yet fully known, and hence the mechanisms responsible for some of the complex flow phenomena that are observed in the human vasculature are not well understood. 18,[24][25][26] Usually, 3D simulations produce such large quantities of data that they are unlikely to be of clinical use unless methods are available to simplify our understanding of the flow dynamics.…”

Section: Introductionmentioning

confidence: 99%

Reducing the data: Analysis of the role of vascular geometry on blood flow patterns in curved vessels

et al. 2012

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“…Since its first demonstration, 11 the secondary flow inside a curved channel [12][13][14][15][16][17][18] has received much attention because it is found in many areas from heat exchangers to human arterial systems. 19,20 All previous experimental works were done with large pipes and utilized laser Doppler anemometry 21,22 or tracers, 11,19,20,23,24 like dye, hydrogen bubble, or powder, to explore the secondary flow.…”

Section: Introductionmentioning

confidence: 99%

Optical sectioning for microfluidics: secondary flow and mixing in a meandering microchannel

2008

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Secondary flow plays a critical function in a microchannel, such as a micromixer, because it can enhance heat and mass transfer. However, there is no experimental method to visualize the secondary flow and the associated mixing pattern in a microchannel because of difficulties in high-resolution, non-invasive, cross-sectional imaging. Here, we simultaneously imaged and quantified the secondary flow and pattern of two-liquid mixing inside a meandering square microchannel with spectral-domain Doppler optical coherence tomography. We observed an increase in the efficiency of two-liquid mixing when air was injected to produce a bubble-train flow and identified the three-dimensional enhancement mechanism behind the complex mixing phenomena. An alternating pair of counterrotating and toroidal vortices cooperated to enhance two-liquid mixing.

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Flow in Curved Pipes

Cited by 1,068 publications

References 0 publications

Engineering fluid flow using sequenced microstructures

Engineering fluid flow using sequenced microstructures

Reducing the data: Analysis of the role of vascular geometry on blood flow patterns in curved vessels

Optical sectioning for microfluidics: secondary flow and mixing in a meandering microchannel

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