Drag Coefficient and Fall Velocity of nonspherical particles

Swamee, Prabhata K.; Ojha, C. S. P.

doi:10.1061/(asce)0733-9429(1991)117:5(660)

Cited by 149 publications

(49 citation statements)

References 2 publications

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“…The settling cylinders were observed to retain their initial orientation during settling, which is opposite to the conclusion of Clift et al [2] (6) However the terminal settling velocity with the above range of Re, the cylinder falls with its axis oriented horizontally [2]. Therefore it doubtful that the findings of Venu Maddhav and Chhabra [4] can be extrapolated to an unconfined environment in which the orientation is not generally horizontal.…”

Section: Clift Et Almentioning

confidence: 73%

“…But like Haider's work, for particles where ψ<0.5, Ganser's work is applicable to disk only. Swamee and Ojha [6] also developed a correlation with the Corey shape factor, β=c/(ab) 1/2 , where a>b>c are the lengths of the three principal axis of the particle. However this parameter is only applicable in the range of 0.3 < β <1, making it unsuitable for long aspect ratio fibres such as those considered here.…”

Section: Clift Et Almentioning

confidence: 99%

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PTV measurement of drag coefficient of fibrous particles with large aspect ratio

Qi¹,

Nathan²,

Kelso³

2012

Powder Technology

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The aerodynamic behaviour of long aspect ratio nylon fibrous particles has been investigated experimentally whilst settling in air under super dilute conditions without any influence of secondary flows and at fibre Reynolds numbers of 0.5 -2 based on fibre diameter. A method for laser-based measurement of the orientations and velocities of fibrous particles is presented. The experimental apparatus employs a two-dimensional Particle Tracking Velocimetry (PTV) to calculate orientation and velocity based on the two end-points. The controlling length scale in the relationship between Reynolds number and drag coefficient was investigated and the equivalent diameter of settling fibre in air was reported.

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Section: Clift Et Almentioning

confidence: 73%

Section: Clift Et Almentioning

confidence: 99%

PTV measurement of drag coefficient of fibrous particles with large aspect ratio

Qi¹,

Nathan²,

Kelso³

2012

Powder Technology

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“…In particular, the following drag laws were selected: Dellino et al (2005), Pfeiffer et al (2005), Ganser (1993), Dioguardi and Mele (2015), and Bagheri and Bonadonna (2016). In the attached supplementary file "2017JB014926-ds01.xls" results from comparisons with other drag laws found in the literature (Chien, 1994;Haider & Levenspiel, 1989;Swamee & Ojha, 1991) are also available in the sheet "Models comparisons." Here we show results from this intercomparison with formulas that are most relevant to volcanology.…”

Section: Comparison With Other Shape-dependent Drag Laws Commonly Usementioning

confidence: 99%

“…AERODYNAMIC DRAG OF IRREGULAR PARTICLES 144 Zhu et al, 2017), pyroclastic flows (e.g., Dellino et al, 2008;, eruptive columns (e.g., Cerminara et al, 2016;Folch et al, 2016), and distal ash clouds (e.g., Beckett et al, 2015;Bonadonna et al, 2012;Bonasia et al, 2010;Costa et al, 2012Costa et al, , 2006). Therefore, a major effort has been posed to find reliable shapedependent drag laws that work on the widest possible range of fluid dynamic regimes quantified by Re (Alfano et al, 2011;Bagheri & Bonadonna, 2016;Chhabra et al, 1999;Chien, 1994;Dellino et al, 2005;Dioguardi et al, 2017;Dioguardi & Mele, 2015;Ganser, 1993;Haider & Levenspiel, 1989;Hölzer & Sommerfeld, 2008;Loth, 2008;Pfeiffer et al, 2005;Swamee & Ojha, 1991;Tran-Cong et al, 2004;Wilson & Huang, 1979). These drag laws are a function of different shape descriptors, among which sphericity Φ is the most widely used.…”

Section: Introductionmentioning

confidence: 99%

A New One‐Equation Model of Fluid Drag for Irregularly Shaped Particles Valid Over a Wide Range of Reynolds Number

2018

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A new drag law for irregularly shaped particles is presented here. Particles are described by a shape factor that takes into account both sphericity and circularity, which can be measured via the most commonly used image particle analysis techniques. By means of the correlation of the drag coefficient versus the particle Reynolds number and the shape factor, a new drag formula, which is valid over a wide range of Reynolds number (0.03–10,000), is obtained. The new model is able to reproduce the drag coefficient of particles measured in terminal velocity experiments with a smaller scatter compared to other laws commonly used in multiphase flow engineering and volcanology. Furthermore, the new formula uses only one equation, whereas previous models, to insure validity over an ample range, made use of a step function that introduces a discontinuity at the switch of equations. Finally, this drag law works in the whole range of variation, from extremely irregular particles to perfect sphere. A code of the iterative algorithm for the drag coefficient calculation and terminal velocity is included in the supporting information both as a Fortran routine and a Matlab function.

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“…Chhabra et al (1999) compared five available drag coefficient correlations for non-spherical particles (Haider and Levenspiel, 1989;Swamee and Ojha, 1991;Ganser, 1993;Chien, 1994;Hartman et al, 1994) by using 1900 data points covering , and particle shape (cylinders, needles, cones, prisms, discs, cubes) from 19 independent studies. Note that the particle sphericity, , is defined as the ratio of the surface area of a sphere having the same volume as the particle to the actual surface area of the non-spherical particle.…”

Section: Translational Motionmentioning

confidence: 99%

Dynamics of single, non-spherical ellipsoidal particles in a turbulent channel flow

Njobuenwu

Fairweather

2015

Chemical Engineering Science

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Using disk, spherical and needle-like particles with equal equivalent volume diameters, the orientational dynamics of non-spherical particles is studied in a turbulent channel flow. An Eulerian-Lagrangian approach based on large eddy simulation with a dynamic sub-grid scale model is used to predict a fully developed gassolid flow at a shear Reynolds number Re = 300. Particle shape and orientation are accounted for by the coupling between Newton's law of translational motion and Euler's law of rotational motion, both in a Lagrangian framework. The particle shapes are simulated using the super-quadrics form, with the dynamically relevant parameters being the particle aspect ratio, equivalent volume diameter and response time. The translational and orientational behaviour of single particles initially released at three different locations in the wall-normal direction are monitored, with analysis showing a clear distinction between the behaviour of the different particle shapes. The results show that turbulent dispersion forces non-spherical particles to have a broad orientation distribution. The orientational states observed include periodic, steady rotation, tumbling, precessing and nutating. Velocity gradient, aspect ratio and particle inertia all have an effect on the alignment of the particle principal axis to the inertial axes. Unlike spherical particles, the disk and needle-like particles display a transition from one orientational state to another, especially when their initial position is in the near-wall region, with the frequency of this transition highest for the disk-like particle. Overall, this study leads to an improved understanding of the significance of shape on particle behaviour which is of relevance to many practical flows.

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Drag Coefficient and Fall Velocity of nonspherical particles

Cited by 149 publications

References 2 publications

PTV measurement of drag coefficient of fibrous particles with large aspect ratio

PTV measurement of drag coefficient of fibrous particles with large aspect ratio

A New One‐Equation Model of Fluid Drag for Irregularly Shaped Particles Valid Over a Wide Range of Reynolds Number

Dynamics of single, non-spherical ellipsoidal particles in a turbulent channel flow

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