Experimental Study of Flow Structures around Side-by-Side Spheres

Pinar, Engin; Şahi̇n, Beşi̇r; Özgören, Muammer; Akıllı, Hüseyin

doi:10.1021/ie4022732

Cited by 20 publications

(9 citation statements)

References 36 publications

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“…In these formations apart from the non-dimensional streamwise distance between the droplets (L/D0), also the cross-stream one (H/D0) can be speculate to play a role; the L and H here correspond to distances between the droplet centres. Regarding the hydrodynamic interaction between rigid particles, the experimental works of [7,8] examined two particles exposed in parallel to a uniform flow of water, with non-dimensional distances between them (H/D0) ranging from 1 up to 2.5 and Re number equal to 5,000. They studied mainly the flow around the particles and concluded that for H/D0=1 (particles are in contact) the particles act as a rigid bluff body, while for H/D0≥2 the interaction between the shedding vortices is minimized as well as the effect of the jet-like flow occurring through them.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of the aerodynamic breakup of a parallel moving droplet cluster

Stefanitsis

Strotos

Νikolopoulos

et al. 2019

International Journal of Multiphase Flow

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The present work examines numerically the aerodynamic breakup of a cluster of Diesel droplets moving in parallel with respect to the gas flow. Two-and three-dimensional simulations of the incompressible Navier-Stokes equations together with the VOF method are performed for Weber (We) numbers in the range of 5 up to 60 and non-dimensional distance between the droplets (H/D0) ranging from 1.25 to 20. The numerical results indicate that the proximity of droplets affects their breakup for distances H/D0≤5. For low droplet proximity distances (H/D0≤2.5), the droplets experience the socalled shuttlecock breakup mode, which has been also identified for droplets in tandem formations in a previous authors' work and is characterized by an oblique peripheral stretching of the droplet. With decreasing H/D0 the breakup initiation time decreases, while the drag coefficient increases relative to that of isolated droplets. When the distance between the droplets is low enough (H/D0<1.5), this can result in critical We number, i.e. minimum We number leading to breakup, lower than that of an isolated droplet at the same conditions.

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Section: Introductionmentioning

confidence: 99%

Numerical investigation of the aerodynamic breakup of a parallel moving droplet cluster

Stefanitsis

Strotos

Νikolopoulos

et al. 2019

International Journal of Multiphase Flow

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show abstract

“…The system PIV system used in this work was extensively described in [34,35]. Thus, data needed for the evaluation of the results are presented here.…”

Section: Experimental Setup and Proceduresmentioning

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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“…PIV allows for practically nonintrusive measurement of the velocity field in contrast to point measurements using other methods that provides plenty of data for validation. Recently, several studies have been done by different researchers in a variety of geometries (Chen and Wu, 2000;Johnson and Patel, 1999;Liang et al, 1996;Maheshwari et al, 2006;Ozgoren, 2013;Ozgoren et al, 2014Ozgoren et al, , 2013Ozgoren et al, , 2011Pinar et al, 2013;Prahl et al, 2007;Tsuji et al, 2003Tsuji et al, , 1982Zhu et al, 1994). This chapter is an article published in Chemical Engineering Journal (Ramezani et al, 2015).…”

Section: Flow Field Investigation Around a Train Of Particles In A Sqmentioning

confidence: 99%

“…Recently, several studies have been done by different researchers in a variety of geometries (Ozgoren, 2013;Ozgoren et al, 2013Ozgoren et al, , 2011Pinar et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Clustering of particles is also of particular interest in such flow systems (Capecelatro et al, 2014). Previous studies have investigated fluid flow around different arrangements of spherical solid particles based on drag force measurement (Liang et al, 1996;Zhu et al, 1994), numerical investigation of flow around multiple spheres (Jadoon et al, 2010;Maheshwari et al, 2006;Prahl et al, 2009Prahl et al, , 2007Tsuji et al, 2003), experimental field measurement of similar geometries (Chen and Wu, 2000;Ozgoren, 2013;Pinar et al, 2013;Tsuji et al, 1982). A fundamental understanding of the basic hydrodynamics in such flow systems is crucial for correctly predicting other aspects of these flows.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of multiphase flow: Mass transfer and fluid flow in Taylor-Couette reactor and velocity field of train of particles in a square duct

Ramezani

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Experimental Study of Flow Structures around Side-by-Side Spheres

Cited by 20 publications

References 36 publications

Numerical investigation of the aerodynamic breakup of a parallel moving droplet cluster

Numerical investigation of the aerodynamic breakup of a parallel moving droplet cluster

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

Experimental investigation of multiphase flow: Mass transfer and fluid flow in Taylor-Couette reactor and velocity field of train of particles in a square duct

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