On the assessment, implementation, validation, and verification of drag and lift forces in gas–liquid applications for the CFD codes FLUENT and CFX


The understanding of two-phase gas–liquid flows is of utmost importance in a large range of industrial applications, including the petrochemical, pharmaceutical, biochemical, nuclear, and metallurgical industries. At ANSYS, significant effort is being made in assessing the physical force models present in both FLUENT and CFX. This includes the investigation of the interfacial closures (drag, lift, wall lubrication, turbulent dispersion, and virtual mass), heat and mass transfer, cavitation, wall boiling, population balance approaches, bubble breakup and coalescence, and turbulence modeling. This assessment is being done with the objective to conduct an audit/validation of the current models, features, and capabilities, as well as the identification and closing of gaps and differences between CFX and FLUENT. The work presented here is mostly focused on the assessment, implementation, and validation of the drag and lift interfacial closures. The numerical assessment and validation are performed using both analytical and industrial-like test cases for complex bubbly flows (both with wall and bulk void fraction maximums), as well as transitional flow from bubbly to slug regime using the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) experimental facility known as MT-Loop.

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


  1. Burns, A., Frank, T., Hamill, I., Shi, J. 2004. The Favre averaged drag model for turbulent dispersion in Eulerian multi-phase flows. In: Proceedings of the 5th International Conference on Multiphase Flow, Paper No. 392.

    Google Scholar 

  2. Ishii, M., Zuber, N. 1979. Drag coefficient and relative velocity in bubbly, droplet or particulate flows. AIChE J, 25: 843–855.

    Article  Google Scholar 

  3. Krepper, E., Lucas, D., Frank, T., Prasser, H.-M., Zwart, P. J. 2008. The inhomogeneous MUSIG model for the simulation of polydispersed flows. Nucl Eng Des, 238: 1690–1702.

    Article  Google Scholar 

  4. Krepper, E., Lucas, D., Prasser, H.-M. 2005. On the modelling of bubbly flow in vertical pipes. Nucl Eng Des, 235: 597–611.

    Article  MATH  Google Scholar 

  5. Legendre, D., Magnaudet, J. 1998. The lift force on a spherical bubble in a viscous linear shear flow. J Fluid Mech, 368: 81–126.

    MathSciNet  Article  MATH  Google Scholar 

  6. Lo, S., Bagatin, R., Masi, M. 2000. The development of a CFD analysis and design tool for air-lift reactors. In: Proceedings of the SAIChE 2000 Conference.

    Google Scholar 

  7. Lucas, D., Krepper, E., Prasser, H.-M. 2005. Development of co-current air-water flow in a vertical pipe. Int J Multiphase Flow, 31: 1304–1328.

    Article  MATH  Google Scholar 

  8. Mei, R. W., Klausner, J. F. 1994. Shear lift force on spherical bubbles. Int J Heat Fluid Fl, 15: 62–65.

    Article  Google Scholar 

  9. Montoya, G. 2015. Development and validation of advanced theoretical modeling for churn-turbulent flows and subsequent transitions. Doctoral Dissertation. Technischen Universität Berlin.

    Google Scholar 

  10. Moraga, F. J., Bonetto, F. J., Lahey, R. T. 1999. Lateral forces on spheres in turbulent uniform shear flow. Int J Multiphase Flow, 25: 1321–1372.

    Article  MATH  Google Scholar 

  11. Rzehak, R., Krepper, E., Ziegenhein, T., Lucas, D. 2014. A baseline model for monodispersed bubbly flows. In: Proceedings of the 10th International Conference on CFD in Oil & Gas, Metallurgical and Process Industries, 83–91.

    Google Scholar 

  12. Saffman, P. G. 1965. The lift on a small sphere in a slow shear flow. J Fluid Mech, 22: 385–400.

    Article  MATH  Google Scholar 

  13. Saffman, P. G. 1968. Corrigendum to: “The lift on a small sphere in a slow shear flow”. J Fluid Mech, 31: 624.

    Article  Google Scholar 

  14. Schiller, L., Naumann, A. 1935. Über die grundlegenden Berechnungen bei der Schwerkraftaufbereitung. Z. Ver. Dtsch. Ing., 77: 318–326.

    Google Scholar 

  15. Tomiyama, A. 1998. Struggle with computational bubble dynamics. Multiphase Sci Tech, 10: 369–405.

    Article  Google Scholar 

  16. Tomiyama, A., Tamai, H., Zun, I., Hosokawa, S. 2002. Transverse migration of single bubbles in simple shear flows. Chem Eng Sci, 57: 1849–1858.

    Article  Google Scholar 

  17. Ziegenhein, T., Rzehak, R., Lucas, D. 2015. Transient simulation for large scale flow in bubble columns. Chem Eng Sci, 122: 1–13.

    Article  Google Scholar 

Download references


The authors would like to acknowledge Paul Gilbert and Patrick Sharkey from ANSYS, UK, for their constant support to this project.

Author information



Corresponding author

Correspondence to Gustavo Montoya.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Montoya, G., Sanyal, J., Braun, M. et al. On the assessment, implementation, validation, and verification of drag and lift forces in gas–liquid applications for the CFD codes FLUENT and CFX. Exp. Comput. Multiph. Flow 1, 255–270 (2019). https://doi.org/10.1007/s42757-019-0032-z

Download citation


  • CFD modeling
  • CFD validation
  • multiphase flow
  • two-fluid model
  • MT-Loop