Skip to main content

DNS using CLSVOF method of single micro-bubble breakup and dynamics in flow focusing


Numerical simulations are performed to investigate the breakup of air bubble in flow focusing configuration; the CLSVOF (coupled level set with volume of fluid) method is employed to track the interface, which allows a better identification of the liquid–gas interface via a function called level set. The CFD simulations showed that the velocity ratio, the interfacial tension, the outer channel diameter, the continuous phase viscosity, the orifice width and length play an important role in the determination of the air bubble’s size and shape. However, at low capillary number, increasing the flow velocity ratio gives a smaller bubble size in shorter time, while the increase in interfacial tension leads to a bigger bubble. Moreover, the carrier fluid is found to slightly affect the bubbling mechanism, while the smallest bubbles were obtained with the smallest orifice size. In addition, three breakup regimes are observed in this device: disc-bubble (DB), elongated bubble (EB) and the slug bubble (SB) regime flows. This work also demonstrates that the CLSVOF is an effective method to simulate the bubbles breakup in flow focusing geometry. In addition, a comparison of our computational simulations with available experimental results reveals reasonably good agreement.

Graphic abstract

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7



Frequency (Hz)


Velocity (m/s)


Unit vector normal to the interface


Curvature of the interface


The surface tension force


Diameter (mm)


Dynamic viscosity (kg/m.s)


Phase fraction (%)


The surface tension coefficient (N/m)


Time (s)






Velocity ratio


Flow focusing


Computational fluid dynamics




Density (kg/m3)


Flow rate


The bubble breakup time


Direct numerical simulation


Volume of fluid method


Lattice Boltzmann


Level set


Coupled LS with VOF method


Surfactant sodium dodecyl sulphate






Outer channel




Dispersed phase


Continuous phase




  • Albadawi A, Donoghue DB, Robinson AJ, Murray DB, Delauré YMC (2013) Influence of surface tension implementation in volume of fluid and coupled volume of fluid with level set methods for bubble growth and detachment. Int J Multiph Flow 53:11–28

    Article  Google Scholar 

  • Antonietti M, Tauer K (2003) 90 years of polymer latexes and heterophase polymerization: more vital than ever. Macromol Chem Phys 204(2):207–219

    Article  Google Scholar 

  • Arias S, Legendre D, González-Cinca R (2012) Numerical simulation of bubble generation in a T-junction. Comput Fluids 56:49–60

    Article  Google Scholar 

  • Baroud CN, Delville J-P, Gallaire F, Wunenburger R (2007) Thermocapillary valve for droplet production and sorting. Phys Rev E 75(4):046302

    Article  Google Scholar 

  • Castro-Hernández E, van Hoeve W, Lohse D, Gordillo JM (2011) Microbubble generation in a co-flow device operated in a new regime. Lab Chip 11(12):2023–2029

    Article  Google Scholar 

  • Chekifi T (2018) Computational study of droplet breakup in a trapped channel configuration using volume of fluid method. Flow Meas Instrum 59:118–125

    Article  Google Scholar 

  • Chekifi T, Dennai B, Khelfaoui R (2015) Numerical simulation of droplet breakup, splitting and sorting in a microfluidic device. FDMP-Fluid dynamics materials processing 11(3):205–220

    Google Scholar 

  • Chekifi T, Dennai B, Khelfaoui R, Maazouzi A (2016) Numerical and experimental investigation of fluidic microdrops manipulation by Fluidic Mono-Stable Oscillator. Int J Fluid Mech Res 43(1):50–61

    Article  Google Scholar 

  • Dollet B, van Hoeve W, Raven JP, Marmottant P, Versluis M (2008) Role of the channel geometry on the bubble pinch-off in flow-focusing devices. Phys Rev Lett 100(3):034504

    Article  Google Scholar 

  • Fu T, Ma Y, Funfschilling D, Li HZ (2009) Bubble formation and breakup mechanism in a microfluidic flow-focusing device. Chem Eng Sci 64(10):2392–2400

    Article  Google Scholar 

  • Ganán-Calvo AM, Gordillo JM (2001) Perfectly monodisperse microbubbling by capillary flow focusing. Phys Rev Lett 87(27):274501

    Article  Google Scholar 

  • Garstecki P, Gitlin I, DiLuzio W, Whitesides GM, Kumacheva E, Stone HA (2004) Formation of monodisperse bubbles in a microfluidic flow-focusing device. Appl Phys Lett 85(13):2649–2651

    Article  Google Scholar 

  • Garstecki P, Fuerstman MJ, Whitesides GM (2005) Nonlinear dynamics of a flow-focusing bubble generator: an inverted dripping faucet. Phys Rev Lett 94(23):234502

    Article  Google Scholar 

  • Garstecki P, Fuerstman MJ, Stone HA, Whitesides GM (2006) Formation of droplets and bubbles in a microfluidic T-junction—scaling and mechanism of break-up. Lab Chip 6(3):437–446

    Article  Google Scholar 

  • Kim J, Lowengrub J (2004) Interfaces and multicomponent fluids. Encyclopedia of Mathematical Physics, pp. 135–144

  • Lu Y, Fu T, Zhu C, Ma Y, Li HZ (2014) Scaling of the bubble formation in a flow-focusing device: role of the liquid viscosity. Chem Eng Sci 105:213–219

    Article  Google Scholar 

  • Mezzenga R, Schurtenberger P, Burbidge A, Michel M (2005) Understanding foods as soft materials. Nat Mater 4(10):729

    Article  Google Scholar 

  • Sussman M (2003) A second order coupled level set and volume-of-fluid method for computing growth and collapse of vapor bubbles. J Comput Phys 187(1):110–136

    MathSciNet  Article  Google Scholar 

  • Sussman M, Puckett EG (2000) A coupled level set and volume-of-fluid method for computing 3D and axisymmetric incompressible two-phase flows. J Comput Phys 162(2):301–337

    MathSciNet  Article  Google Scholar 

  • Tadros TF (1993) Industrial applications of dispersions. Adv Coll Interface Sci 46:1–47

    Article  Google Scholar 

  • van Hoeve W, Dollet B, Versluis M, Lohse D (2011) Microbubble formation and pinch-off scaling exponent in flow-focusing devices. Phys Fluids 23(9):092001

    Article  Google Scholar 

  • Wang ZL (2015) Speed up bubbling in a tapered co-flow geometry. Chem Eng J 263:346–355

    Article  Google Scholar 

  • Wang K, Xie L, Lu Y, Luo G (2013) Generating microbubbles in a co-flowing microfluidic device. Chem Eng Sci 100:486–495

    Article  Google Scholar 

  • Whitesides GM (2006) The origins and the future of microfluidics. Nature 442(7101):368

    Article  Google Scholar 

  • Yobas L, Martens S, Ong W-L, Ranganathan N (2006) High-performance flow-focusing geometry for spontaneous generation of monodispersed droplets. Lab Chip 6(8):1073–1079

    Article  Google Scholar 

Download references


The author would like to acknowledge the valuable comments and suggestions of the reviewers, which has improved the quality of this paper.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Tawfiq Chekifi.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Chekifi, T., Boukraa, M. & Aissani, M. DNS using CLSVOF method of single micro-bubble breakup and dynamics in flow focusing. J Vis 24, 519–530 (2021).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


  • Bubbling
  • Multiphase flow
  • CFD and flow focusing