The flow characteristics between two interactive spheres

Chen, R.C.; Wu, Jo-Ti

doi:10.1016/s0009-2509(99)00390-5

Cited by 66 publications

(30 citation statements)

References 10 publications

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“…Measurements in the laminar boundary-layer flow regime at moderate ReD ( I 100) indicate drag coefficient dependencies on ReD, on the relative orientation of the axis of the array of spheres to the flow (0" approximately an order of magnitude (Chen and Wu 2000, pg. 1 147) or increasing p/D to a value of 4 (Chen andWu 2000, p. 1149, Figures 5, 9, 12). Therefore, the model is conservatively limited to reproduce the primary sensitivity to O that is observed in the experiments, while neglecting the reduction in the magnitude of the interactions between the pair of spheres that occurs with increasing values of p. The drag coefficient required in Equation 1-12 is calculated as the product of two functions, where, CD/CDo = scaled drag coefficient for an obstruction with an interacting neighbor [-I CDo = drag coefficient for an individual obstruction in a free fluid stream…”

Section: -31 Parameter Valuesmentioning

confidence: 90%

“…The assumed acceleration and duration are highly conservative for seismic disturbances. Chen and Wu (2000) perform experiments measuring the drag characteristics of a test sphere in a Newtonian fluid and in the presence of one neighboring sphere of equivalent diameter. Measurements in the laminar boundary-layer flow regime at moderate ReD ( I 100) indicate drag coefficient dependencies on ReD, on the relative orientation of the axis of the array of spheres to the flow (0" approximately an order of magnitude (Chen and Wu 2000, pg.…”

Section: -31 Parameter Valuesmentioning

confidence: 99%

“…The angular dependence of the scaled drag coefficient for spheres (Chen and Wu 2000, Figure 5c, Vd=1/3) is here applied to the cylindrical geometry of the SNF rods. This extension is valid because the third-dimensional flow effects that arise for individual spheres, but are negligible for flow around individual cylinders with large Lr/Dr,, at low and moderate ReD, result in a uniform shift of the drag coefficient values over a broad range of ReD (0.1 5 ReD I lo6) between the two obstruction geometries (see Schlichting 1987, pg.…”

Section: -31 Parameter Valuesmentioning

confidence: 99%

See 2 more Smart Citations

Generic Degraded Congiguration Probability Analysis for DOE Codisposal Waste Package

Deng¹,

Saglam²,

Gratton³

2001

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Section: -31 Parameter Valuesmentioning

confidence: 90%

Section: -31 Parameter Valuesmentioning

confidence: 99%

Section: -31 Parameter Valuesmentioning

confidence: 99%

See 1 more Smart Citation

Generic Degraded Congiguration Probability Analysis for DOE Codisposal Waste Package

Deng¹,

Saglam²,

Gratton³

2001

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“…Navier-Stokes equations stay valid throughout the full range of flow regimes, scales, and contexts. They are preferentially used where much complexity is needed, often when relevant simplified flow descriptions could not be derived, for example, for particle-scale applications (Chen and Wu, 2000;Wu and Lee, 2001;Feng and Michaelides, 2002), overland flow (Dunkerley, 2003(Dunkerley, , 2004, or flows over pronounced bedforms Schmeeckle and Nelson, 2003). A very wide review of numerical methods and applications for the NS equations is provided by Gresho and Sani (1998) and a benchmark of numerous solvers by Turek (1999).…”

Section: Water Flowmentioning

confidence: 99%

Determinants of modelling choices for 1-D free-surface flow and morphodynamics in hydrology and hydraulics: a review

Cheviron

Moussa²

2016

Hydrol. Earth Syst. Sci.

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Abstract. This review paper investigates the determinants of modelling choices, for numerous applications of 1-D freesurface flow and morphodynamic equations in hydrology and hydraulics, across multiple spatiotemporal scales. We aim to characterize each case study by its signature composed of model refinement (Navier-Stokes: NS; Reynolds-averaged Navier-Stokes: RANS; Saint-Venant: SV; or approximations to Saint-Venant: ASV), spatiotemporal scales and subscales (domain length: L from 1 cm to 1000 km; temporal scale: T from 1 s to 1 year; flow depth: H from 1 mm to 10 m; spatial step for modelling: δL; temporal step: δT ), flow typology (Overland: O; High gradient: Hg; Bedforms: B; Fluvial: F), and dimensionless numbers (dimensionless time period T * , Reynolds number Re, Froude number Fr, slope S, inundation ratio z , Shields number θ ). The determinants of modelling choices are therefore sought in the interplay between flow characteristics and cross-scale and scale-independent views. The influence of spatiotemporal scales on modelling choices is first quantified through the expected correlation between increasing scales and decreasing model refinements (though modelling objectives also show through the chosen spatial and temporal subscales). Then flow typology appears a secondary but important determinant in the choice of model refinement. This finding is confirmed by the discriminating values of several dimensionless numbers, which prove preferential associations between model refinements and flow typologies. This review is intended to help modellers in positioning their choices with respect to the most frequent practices, within a generic, normative procedure possibly enriched by the community for a larger, comprehensive and updated image of modelling strategies.

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“…In the numerical approaches, [13,[23][24][25][26][27][28][29] can be given as exemplary studies. These studies are similar to each other in placing a secondary sphere around a single sphere and investigating the flow structure.…”

Section: Introductionmentioning

confidence: 99%

Wake structures of two side by side spheres in a tripped boundary layer flow

Canlı

Özgören

Doğan

et al. 2014

EPJ Web of Conferences

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Abstract. Two independent spheres were placed in a side by side arrangement and flow structure in the wake region of the spheres was investigated with a Particle Image Velocimetry (PIV) system when the spheres were in a boundary layer over a flat plate as a special case. Reynolds number was 5000 based on the sphere diameter which was 42.5 mm. Boundary layer was tripped 8mm away from the leading edge of the flat plate with a 5 mm trip wire. The thickness of the hydrodynamically developed boundary layer was determined as 63mm which was larger than the sphere diameter of D=42.5mm. Wake region of the spheres was examined from point of flow physics for the different sphere locations in the ranges of 0G/D 1.5 and 0S/D 1.5 where G and S were the distance between the spheres and the distance between the bottom point of the spheres and the flat plate surface, respectively. Depending on the different sphere locations, instantaneous and time averaged vorticity data, scalar values of time-averaged velocity components and their root mean square (rms) values and time averaged vorticity data are presented in the study for the evaluation of wake region of the spheres. It is demonstrated that the gap between the two spheres and the interaction between the gap and the boundary layer greatly affects flow pattern, especially when spheres are located near to the flat plate surface, i.e. S/D=0.1 for 0G/D 1.5. Different distances between the spheres resulted in various flow patterns as the spheres were approached to the flat plate. The distance S/D=0.1 for all gap values has the strongest effect on the wake structures. Beyond G/D=1.0, the sphere wakes tend to be similar to single sphere case. The instantaneous vorticity fields of the side by side arrangements comprised wavy structures in higher level comparing to an individual sphere case. The gap flow intensifies the occurrence of small scale eddies in the wake region. The submersion rate of the spheres actually determines the characteristics of the wake region and is affected from boundary layer flow in a gradually decreasing manner.

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The flow characteristics between two interactive spheres

Cited by 66 publications

References 10 publications

Generic Degraded Congiguration Probability Analysis for DOE Codisposal Waste Package

Generic Degraded Congiguration Probability Analysis for DOE Codisposal Waste Package

Determinants of modelling choices for 1-D free-surface flow and morphodynamics in hydrology and hydraulics: a review

Wake structures of two side by side spheres in a tripped boundary layer flow

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