Numerical Study of the Entrainment and Transport of Gas Bubbles by a Vortex Ring

Uchiyama, Tomomi; Yoshii, Yutaro

doi:10.4172/2157-7048.1000245

Cited by 4 publications

(9 citation statements)

References 17 publications

(22 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the interaction between a vortical flow and light particles cannot be inferred from the results with heavy particles. Uchiyama and Yoshii (2015) numerically simulated the entrainment and transport of the gas bubbles by a vortex ring at Re Γ = 400, 500 and 600. The total volume of the entrained bubbles in the vortex core is higher for lower values of Re Γ .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical simulation of the interaction between a vortex ring and a bubble plume

Nguyen

Degawa

Uchiyama

2019

HFF

Self Cite

View full text Add to dashboard Cite

Purpose This paper aims to provide discussions of a numerical method for bubbly flows and the interaction between a vortex ring and a bubble plume. Design/methodology/approach Small bubbles are released into quiescent water from a cylinder tip. They rise under the buoyant force, forming a plume. A vortex ring is launched vertically upward into the bubble plume. The interactions between the vortex ring and the bubble plume are numerically simulated using a semi-Lagrangian–Lagrangian approach composed of a vortex-in-cell method for the fluid phase and a Lagrangian description of the gas phase. Findings A vortex ring can transport the bubbles surrounding it over a distance significantly depending on the correlative initial position between the bubbles and the core center. The motion of some bubbles is nearly periodic and gradually extinguishes with time. These bubble trajectories are similar to two-dimensional-helix shapes. The vortex is fragmented into multiple regions with high values of Q, the second invariant of velocity gradient tensor, settling at these regional centers. The entrained bubbles excite a growth rate of the vortex ring's azimuthal instability with a formation of the second- and third-harmonic oscillations of modes of 16 and 24, respectively. Originality/value A semi-Lagrangian–Lagrangian approach is applied to simulate the interactions between a vortex ring and a bubble plume. The simulations provide the detail features of the interactions.

show abstract

Section: Introductionmentioning

confidence: 99%

“…In this approach, the methods used to solve for the liquid phase are called semi-Lagrangian, hybrid-Eulerian–Lagrangian, or vortex-in-cell methods. Examples of investigations related to the semi-L–L approach are Nguyen et al (2019), Wang et al (2013) and Uchiyama and Yoshii (2015) and Uchiyama et al (2015).…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of the interaction between a vortex ring and a bubble plume

Nguyen

Degawa

Uchiyama

2019

HFF

Self Cite

View full text Add to dashboard Cite

show abstract

“…Research on such interactions has scarcely been reported except for the studies of Sridhar and Katz [6], [7] and Higuera [8], which investigated the motion of a single bubble in a vortex core and the bubble-induced deformation of a vortex ring. Thus, the current authors [9][10][11][12] researched possible entrainment and transport of small bubbles by a vortex ring. Uchiyama [9] conducted a numerical simulation of a water jet laden with small air bubbles and showed that a vortex ring induced near the nozzle outlet by an axisymmetric disturbance involves the bubbles and convects with the bubbles along the jet centerline.…”

Section: Introductionmentioning

confidence: 99%

“…Uchiyama [9] conducted a numerical simulation of a water jet laden with small air bubbles and showed that a vortex ring induced near the nozzle outlet by an axisymmetric disturbance involves the bubbles and convects with the bubbles along the jet centerline. Uchiyama and Yoshii [10] simulated the bubble motion and the behavior of a vortex ring launched toward a bubble cluster, and they demonstrated the entrainment and transport of the bubbles by the vortex ring as well as the change in the strength of the vortex ring because of the entrained bubbles. Wang et al [11] simulated the interaction between a bubble plume and a vortex ring and reported the effect of the bubbles on the behavior of the vortex ring.…”

Section: Introductionmentioning

confidence: 99%

Control of Air Bubble Cluster by a Vortex Ring Launched into Still Water

Uchiyama¹,

Kusamichi²

2017

IJCEA

Self Cite

View full text Add to dashboard Cite

An experimental study searching for the possible generation and transport of a bubble cluster by a vortex ring in water is performed. A vortex ring is launched vertically upward into a water tank by discharging the water from a cylinder mounted at the bottom of the tank with a piston. Air bubbles are successively injected into the vortex ring from a needle attached to the cylinder outlet. The cylinder inner diameter D 0 and the piston stroke L 0 are 42.5 mm and 100 mm, respectively. The circulation of the vortex ring is less than 20000, and accordingly laminar vortex rings are launched. The mean diameter of the bubbles is 3.4 mm. The generation of bubble cluster and transport of the cluster by the vortex ring can be classified into four patterns according to the piston velocity (strength of the vortex ring) and the air volumetric flow rate. When the strength of the vortex ring is low, the bubbles are less affected by the vortex ring and instead rise with the buoyant force at a higher velocity than the vortex ring. With an increase in the strength of the vortex ring, the bubbles are entrained in the vortex core and form a cluster. The bubbles entrained in the vortex core circumferentially disperse around the vertical axis of the vortex ring, and they are successfully transported by the convection of the vortex ring. The convection velocity of the vortex ring is scarcely affected by the entrained bubbles, but the radius is enlarged slightly. The circulation of a vortex ring that entrains and transports air bubbles in this study is nearly accurately predicted by the formula of Milenkovic et al., which gives the circulation of a vortex ring entraining a single bubble in the vortex core. Index Terms-Bubble cluster, bubble entrainment, vortex ring, vorticity, visualization.

show abstract

“…Uchiyama [1] conducted a numerical simulation of a water jet laden with small air bubbles and showed that a vortex ring, induced near the nozzle outlet by an axisymmetric disturbance, incorporates the bubbles and convects with them along the jet centerline. Uchiyama and Yoshii [2] simulated the bubble motion and behavior of a vortex ring launched toward a bubble cluster. Their simulation found that the bubbles are entrained and transported by the vortex ring and that the strength of the vortex ring is affected by the entrained bubbles.…”

Section: Introductionmentioning

confidence: 99%

Generation and Transport of Solid Particle Clusters Using a Vortex Ring Launched into Water

Uchiyama¹,

Yano²,

Degawa³

2017

IJCEA

Self Cite

View full text Add to dashboard Cite

Abstract-A vortex ring launched into quiescent water is used to generate and transport solid particle clusters. A vortex ring launcher, comprising a cylinder and piston, is mounted at the bottom of a water tank. One-hundred spherical, polyacetal particles (mean diameter: 1.52 mm, density: 1417 kg/m 3 ) are placed on a mesh stretched near the cylinder outlet. The piston is used to discharge water in the cylinder vertically upward into the tank; this launches a particle-laden vortex ring. This solid-liquid two-phase flow is investigated at the Reynolds number Re, defined by the piston velocity and the cylinder diameter, of 6500, 7500, and 13000. When Re=6500, the particles are not entrained in the vortex ring, and therefore a cluster is not produced. Particles are entrained just after the launch of vortex rings at Re=7500 and 13000. These particle clusters are transported by the convection of the vortex ring. The velocity of water in the central vertical cross-section of the vortex ring decreases because of the particles, resulting in decreased circulation of the vortex ring. This reduction is more severe for lower Re.Index Terms-Solid-liquid, two-phase flow, vortex ring, particle entrainment, Piv.

show abstract

Numerical Study of the Entrainment and Transport of Gas Bubbles by a Vortex Ring

Cited by 4 publications

References 17 publications

Numerical simulation of the interaction between a vortex ring and a bubble plume

Numerical simulation of the interaction between a vortex ring and a bubble plume

Control of Air Bubble Cluster by a Vortex Ring Launched into Still Water

Generation and Transport of Solid Particle Clusters Using a Vortex Ring Launched into Water

Contact Info

Product

Resources

About