Coherent Turbulent Structures within Open-Channel Lateral Cavities

Mignot, Emmanuel; Brevis, Wernher

doi:10.1061/(asce)hy.1943-7900.0001698

Cited by 11 publications

(9 citation statements)

References 22 publications

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“…Because the fluid velocities within the DEPs are significantly smaller than the ones within the TPs, a detailed understanding of such velocity field requires a multi-scale description. Although Eulerian velocity measurement techniques such as Particle Image Velocimetry (PIV) has been used to quantify the fluid velocity inside cavities 52 , unfortunately it is challenging to simultaneously resolve all the scales of such flow-fields in high-resolution using such methods (see Supplementary Fig. 1) .…”

Section: Resultsmentioning

confidence: 99%

Structure induced laminar vortices control anomalous dispersion in porous media

et al. 2022

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Natural porous systems, such as soil, membranes, and biological tissues comprise disordered structures characterized by dead-end pores connected to a network of percolating channels. The release and dispersion of particles, solutes, and microorganisms from such features is key for a broad range of environmental and medical applications including soil remediation, filtration and drug delivery. Yet, owing to the stagnant and opaque nature of these disordered systems, the role of microscopic structure and flow on the dispersion of particles and solutes remains poorly understood. Here, we use a microfluidic model system that features a pore structure characterized by distributed dead-ends to determine how particles are transported, retained and dispersed. We observe strong tailing of arrival time distributions at the outlet of the medium characterized by power-law decay with an exponent of 2/3. Using numerical simulations and an analytical model, we link this behavior to particles initially located within dead-end pores, and explain the tailing exponent with a hopping across and rolling along the streamlines of vortices within dead-end pores. We quantify such anomalous dispersal by a stochastic model that predicts the full evolution of arrival times. Our results demonstrate how microscopic flow structures can impact macroscopic particle transport.

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Section: Resultsmentioning

confidence: 99%

Structure induced laminar vortices control anomalous dispersion in porous media

et al. 2022

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“…Therefore, the amplitudes measured by the ultrasonic gauge (at U 1 ) are considered suboptimal to estimate the amplitude of the standing waves inside the cavity. Similarly, the surface registrations by the downstream pressure sensor (P d ) are influenced by the fluctuating inflow of vortices entering the cavity after impingement [13], creating a local enhancement of the potential energy but also local surface irregularities. In contrast, the upstream pressure sensor (P u ) seems less affected by the vortex dynamics (i.e., the typical free-surface depressions occurring with vortices) and mean recirculating flow within the cavity, which motivates the use of the upstream pressure registrations to investigate the amplitude of seiching in function of the Froude number in Sec.…”

Section: A Laboratory Facilitymentioning

confidence: 99%

“…The recirculating flow within the cavity exchanges mass and momentum with the main stream through the mixing layer that develops at the interface between the main stream and the cavity [9][10][11]. This mixing layer is characterized by the advection of quasiperiodic, large-scale vortices [10,12,13] that are shed from the upstream corner of the interface. Their impingement [3,14] on the downstream corner of the interface excites local free-surface oscillations and an intermittent inflow toward the cavity [6,9].…”

Section: Introductionmentioning

confidence: 99%

Experimental study of bidirectional seiching in an open-channel, lateral cavity in the time and frequency domain

et al. 2020

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“…Numerous researchers have studied the 3D flow pattern inside the cavity 2,3,14,15 and the coherent turbulent structures that arise at the interface between the main stream and the cavity. 3,14,[16][17][18][19] Figure 1 gives a schematic overview of the main flow phenomena, detailed below, in and around such a simplified (square) lateral embayment.…”

Section: B State Of the Art: 3d Flow Fieldmentioning

confidence: 99%

Lagrangian study of the particle transport past a lateral, open-channel cavity

et al. 2021

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This paper presents a Lagrangian laboratory study of the passive tracer transport in and around a lateral, open-channel (square) cavity. Using 3D-particle tracking velocimetry (PTV), the trajectories of neutrally buoyant seeding particles are measured and analyzed to investigate the processes governing the particle exchanges between the cavity and the adjacent main stream for a selected subcritical flow condition. The tracked particles are classified using a Lagrangian approach based on their start and end positions, i.e., the cavity or the main stream region. Next, the spatial distribution of the particles at the main stream-cavity interface is analyzed to distinguish the typical transport processes of the different particle classes and identify preferential zones of net particle inflow, net particle outflow, and local zigzagging across the interface. Finally, this paper investigates the influence of the zigzag motion of particles on the (net) mass exchange coefficient. Derived from the same 3D-PTV dataset, a comparison between the common Eulerian (velocity-based) and Lagrangian mass exchange coefficients suggests that the transverse velocity method overestimates the net exchange significantly because of the particle zigzag motions.

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Coherent Turbulent Structures within Open-Channel Lateral Cavities

Cited by 11 publications

References 22 publications

Structure induced laminar vortices control anomalous dispersion in porous media

Structure induced laminar vortices control anomalous dispersion in porous media

Experimental study of bidirectional seiching in an open-channel, lateral cavity in the time and frequency domain

Lagrangian study of the particle transport past a lateral, open-channel cavity

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