Spatio-temporal patterns of sediment particle movement on 2D and 3D bedforms

Tsubaki, Ryota; Baranya, Sándor; Muste, Marian; Toda, Yuji

doi:10.1007/s00348-018-2551-y

Cited by 22 publications

(41 citation statements)

References 36 publications

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“…A different size of IA yields different velocity data time series for the same extraction location. The work of Tsubaki et al (2018) is more similar to the conditions of the present study (sand motion over dunes). The size of IA and time step needs to be chosen carefully as a function of particle displacement variation (magnitude and orientation), while also considering the number and size of particles in an IA.…”

Section: Automated Analytical Methodologysupporting

confidence: 75%

“…Their study was for weak transport of 3 mm (light-weight) grains. The work of Tsubaki et al (2018) is more similar to the conditions of the present study (sand motion over dunes). An ensemble correlation PIV approach is used to cope with the 'limited image quality', which is valid for image sets recorded at high spatial and temporal resolution relative to the scale of turbulence, according to Westerweel et al (2004).…”

Section: Automated Analytical Methodologysupporting

confidence: 75%

“…We manually traced~40% of the particles identified in the IoD as moving particles ( Figure 5). To further enhance the quality of the spatial-average estimator, we apply ensemble averaging of the spatial correlation estimate to 10 successive image pairs as described in Westerweel et al (2004) and Tsubaki et al (2018). It is found that mean particle displacement approaches a constant value if the smallest IA is higher than 80 pixels (~0.018 m).…”

Section: Automated Analytical Methodologymentioning

confidence: 99%

“…The manual tracing validation set was used to find the 'optimum' settings for the automated PIV calculations for our images. To further enhance the quality of the spatial-average estimator, we apply ensemble averaging of the spatial correlation estimate to 10 successive image pairs as described in Westerweel et al (2004) and Tsubaki et al (2018). This procedure gives reliable results for situations of Brownian motion and low image density using micro-PIV (small tracer particles observed at high magnification).…”

Section: Automated Analytical Methodologymentioning

confidence: 99%

“…These studies are not necessarily applicable to dunes, due to (i) variations in sediment sizes, (ii) non-uniform flow over the dune slope and (iii) higher mobility conditions. Visualization techniques to measure sediment transport, and not only individual particle motion, over dunes are limited (Tsubaki et al, 2018). Figure 1 shows the existence of a measurement gap from highfrequency imagery for higher Shields numbers and lower Bonnefille numbers, which are conditions in which bedforms form.…”

Section: Introductionmentioning

confidence: 99%

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Sand particle velocities over a subaqueous dune slope using high‐frequency image capturing

Scheltinga

Coco

Friedrich

2019

Earth Surf Processes Landf

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This work presents measurements and analysis of sand particle velocities over a subaqueous dune with median sand diameter of 0.85 mm. Time‐lapse images of the mobile bed and an automated particle image velocimetry (PIV)‐based cross‐correlation method are used to obtain mean velocity of sand particles. This technique is shown to be consistent with measurements obtained with manual tracing. The measurements indicate an increase in mean particle velocity over a dune slope. Three regions are distinguished over the dune slope: (1) region of fluctuating particle velocity, (2) region of increasing particle velocity, and (3) region of maximum particle velocity. The observations are aligned with experimental and numerical modelling studies, indicating fluctuations in flow velocity over a dune stoss slope. We furthermore show that the standard deviation of the mean particle velocity is affected by the slope location and decreases from the lower slope towards the upper slope. The particle velocity variability is discussed in the context of general onset and cessation of sediment transport, the effect of the reattachment zone, sweep‐transport events, and the existence of superimposed bedforms. With this work we bridge the gap between measurements of bedload transport at the particle‐scale and at the bedform‐scale. © 2019 John Wiley & Sons, Ltd.

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Section: Automated Analytical Methodologysupporting

confidence: 75%

Section: Automated Analytical Methodologysupporting

confidence: 75%

Section: Automated Analytical Methodologymentioning

confidence: 99%

Section: Automated Analytical Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Sand particle velocities over a subaqueous dune slope using high‐frequency image capturing

Scheltinga

Coco

Friedrich

2019

Earth Surf Processes Landf

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Advanced methods to investigate hydro‐morphological processes in open‐water environments

Haun

Dietrich

2021

Earth Surf Processes Landf

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Hydro‐morphology describes the interactions between water and sediments in fluvial systems and the corresponding processes across all spatial and temporal scales. The results are natural and anthropogenically influenced bed structures and fluvial landforms. However, many of these hydro‐morphological processes cannot be described analytically yet, as a result of their stochastic behaviour and the multitude of processes involved across spatial and temporal scales. Deeper knowledge of these processes is essential, not only for understanding the system itself, but also for practical applications, which rely on correct and reliable investigations of these processes. During the European Geoscience Union (EGU) General Assembly (GA) 2018 in Vienna, Austria, the conveners of the session on “Measurements, monitoring and numerical modelling of sedimentary and hydro‐morphological processes in open‐water environments” had the idea of initiating a special issue, containing a collection of recent achievements in this research field. The aim of this extended introduction is twofold. First, an overview on research needs in investigating hydro‐morphological processes in open‐water environments is given in this article. Second, recently published studies that aim to improve the understanding of hydro‐morphological processes in rivers, lakes and reservoirs by innovative measurement approaches are discussed. In addition to submitted papers collected from the EGU GA in 2017, 2018 and 2019, related studies published in Earth Surface Processes and Landforms (ESPL) over the last two years are also incorporated into this special issue. The papers selected cover a wide range of studies with differing spatial and temporal resolutions. This broad spectrum of different scales clearly indicates the challenges associated with the development and use of advanced methods for investigating hydro‐morphological processes in open‐water environments.

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LSPIV analysis of ship-induced wave wash

Fleit

Baranya

2022

Exp Fluids

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Ship-induced wave wash affects the hydromorphological and ecological state of rivers through various mechanisms. The direct proximity of the riverbank is usually the most exposed, as the hydrodynamic stresses are the highest in these shallow water areas. Contrary to the steady and almost still, natural flow conditions (i.e., no waves of anthropogenic source), shoaling and breaking of ship waves increase the hydrodynamic stresses by orders of magnitudes, having notable ecological consequences, and resulting in bank erosion as well. Due to the shallow water depths and temporary drying, conventional measurement techniques are no longer applicable in these areas. In this study, large-scale particle image velocimetry (LSPIV) is used to quantify the prevailing flow conditions. In the absence of ground truth data in the wave breaking region, a high-resolution computational fluid dynamics model—verified with field pressure and acoustic Doppler velocimetry data—is used for the cross-validation of the LSPIV results. The results underline the applicability of LSPIV for the hydrodynamic analysis of wave velocities in this special riverine swash zone, which is of key importance from the aspect of ecology and bank erosion as well. Graphical abstract

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Spatio-temporal patterns of sediment particle movement on 2D and 3D bedforms

Cited by 22 publications

References 36 publications

Sand particle velocities over a subaqueous dune slope using high‐frequency image capturing

Sand particle velocities over a subaqueous dune slope using high‐frequency image capturing

Advanced methods to investigate hydro‐morphological processes in open‐water environments

LSPIV analysis of ship-induced wave wash

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