The behavior of large particles falling in quiescent liquids

Stringham, G.E.; Simons, Daryl B.; Guy, Harold P.

doi:10.3133/pp562c

Cited by 90 publications

(80 citation statements)

References 9 publications

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“…Furthermore, VP, FD, and CD varied within the following intervals: 0.12 m/s < VP < 0.31 m/s, 0.5×10 -3 N < FD < 4.2×10 -3 N, and 0.32 < CD < 7.0. For the same range of ReP, the large values of CD achieved for this disk agreed with the data reported by reported by Stringham et al [15].…”

Section: Diskssupporting

confidence: 82%

“…It was observed that at such low ReP the fall was steady with the maximum area of the disk projected perpendicular to the direction of motion, as reported by Stringham et al [15]. Nonetheless, contrary to their assumption that the secondary motions for disks arise at ReP > 400, it was found here that they can appear at considerably lower values.…”

Section: Diskscontrasting

confidence: 52%

“…An alternative way to generate 3D data is the approach used by Stringham et al [15], which consists on placing two cameras at right angle with respect to each other, so that the motion of the particles is recorded in two perpendicular planes. Marchildon et al [14] and Veldhuis et al [12,13,23] also employed a similar configuration but using only one camera and an arrangement of perpendicular mirrors to see the motion on both normal planes.…”

Section: Methodsmentioning

confidence: 99%

“…Stringham et al [15] have found that the orientation of a disk in free fall changes after certain value of ReP as consequence of alterations in the pressure distribution around the object. They witnessed the presence of oscillation, gliding, and tumbling for ReP > 400.…”

Section: Introductionmentioning

confidence: 99%

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Study of drag and orientation of regular particles using stereo vision, Schlieren photography and digital image processing

Carranza

Zhang

2017

Powder Technology

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A new experimental, image-based methodology suitable to track the changes in orientation of non-spherical particles and their influence on the drag coefficient as they settle in fluids is presented. Given the fact that non-spherical solids naturally develop variations in their angular orientation during the fall, none-intrusiveness of the technique of analysis is of paramount importance in order to preserve the particle/fluid interaction undisturbed. Three-dimensional quantitative data about the motion parameters is obtained through single-camera stereo vision whilst qualitative visualizations of the adjacent fluid patterns are achieved with Schlieren photography. The methodology was validated by comparing the magnitudes of the drag coefficient of a set of spherical particles at terminal velocity conditions against those estimated from drag correlations published in the literature. A noteworthy similarity was attained. During the fall of non-spherical solids, once the particle Reynolds number approximated 163 for disks, and 240 for cylinders, or exceeded those values, secondary motions composed by regular oscillations and tumbling were present. They altered the angular orientation of the particles with respect to the main motion direction and caused complete turbulent patterns in the surrounding flow, therefore affecting the instantaneous projected area, drag force, and coefficient of resistance. The impact of the changes in angular orientation onto the drag coefficient was shown graphically as a means for reinforcing existing numerical approaches, however, an explicit relation between both variables could not be observed.

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Section: Diskssupporting

confidence: 82%

Section: Diskscontrasting

confidence: 52%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study of drag and orientation of regular particles using stereo vision, Schlieren photography and digital image processing

Carranza

Zhang

2017

Powder Technology

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“…In terms of aerodynamics, shape has a direct impact on the drag forces acting on rising and falling particles (Stringham et al, 1969;Bursik, 1989;Ganser, 1993;Mitchell, 1996;Chhabra et al, 1999;Mele et al, 2011;Dellino et al, 2012), which in turn influence the settling velocity (Wilson and Huang, 1979;Coltelli et al, 2008;Alfano et al, 2011), the atmospheric residence time (Riley et al, 2003), and the transport distance and dispersal of tephra (Sparks et al, 1997;Scollo et al, 2008). The aerial behavior of ash is also indirectly influenced by the surface-to-volume ratio, which affects the propensity of particles to form aggregates, both in dry and wet environments (e.g.…”

Section: Introduction and Previous Workmentioning

confidence: 99%

High-resolution 3D analyses of the shape and internal constituents of small volcanic ash particles: The contribution of SEM micro-computed tomography (SEM micro-CT)

Vonlanthen

Rausch

Ketcham

et al. 2015

Journal of Volcanology and Geothermal Research

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The morphology of small volcanic ash particles is fundamental to our understanding of magma fragmentation, and in transport modeling of volcanic plumes and clouds. Until recently, the analysis of 3D features in small objects (b250 μm) was either restricted to extrapolations from 2D approaches, partial stereo-imaging, or CT methods having limited spatial resolution and/or accessibility. In this study, an X-ray computed-tomography technique known as SEM micro-CT, also called 3D X-ray ultramicroscopy (3D XuM), was used to investigate the 3D morphology of small volcanic ash particles (125-250 μm sieve fraction), as well as their vesicle and microcrystal distribution. The samples were selected from four stratigraphically well-established tephra layers of the Meerfelder Maar (West Eifel Volcanic Field, Germany). Resolution tests performed on a Beametr v1 pattern sample along with Monte Carlo simulations of X-ray emission volumes indicated that a spatial resolution of 0.65 μm was obtained for X-ray shadow projections using a standard thermionic SEM and a bulk brass target as X-ray source. Analysis of a smaller volcanic ash particle (64-125 μm sieve fraction) showed that features with volumes N 20 μm 3 (~3.5 μm in diameter) can be successfully reconstructed and quantified. In addition, new functionalities of the Blob3D software were developed to allow the particle shape factors frequently used as input parameters in ash transport and dispersion models to be calculated. This study indicates that SEM micro-CT is very well suited to quantify the various aspects of shape in fine volcanic ash, and potentially also to investigate the 3D morphology and internal structure of any object b 0.1 mm 3 .

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Experiments on and Simulations of Hollow Cylinders Falling through Quiescent Liquids

Lu,

Zhang,

et al. 2023

Chem Eng & Technol

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Quantitative visualization experiments of hollow cylinders falling through a Newtonian liquid were performed. The Archimedes number was in the range 5 to 105, the length/outer diameter ratio of the cylinders was in the range 2.5–10, and the inner/outer diameter ratio was 0–0.85. The definition of the Archimedes number includes the inner and outer cylinder diameters, and it is shown that cylinders with the same Archimedes number having different diameter ratios behave similarly. Particle‐resolved simulations were used to enhance the insight into the fluid flow generated by the settling cylinder. They were also used to assess the flow through a hollow cylinder during settling.

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The behavior of large particles falling in quiescent liquids

Cited by 90 publications

References 9 publications

Study of drag and orientation of regular particles using stereo vision, Schlieren photography and digital image processing

Study of drag and orientation of regular particles using stereo vision, Schlieren photography and digital image processing

High-resolution 3D analyses of the shape and internal constituents of small volcanic ash particles: The contribution of SEM micro-computed tomography (SEM micro-CT)

Experiments on and Simulations of Hollow Cylinders Falling through Quiescent Liquids

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