Journal of Hydrodynamics

, Volume 31, Issue 2, pp 224–230 | Cite as

Comparisons and analyses of vortex identification between Omega method and Q criterion

  • Yu-ning Zhang
  • Xiao-yu Wang
  • Yu-ning Zhang
  • Chaoqun LiuEmail author
Special Column for Symposium on Vortex Identification Methods and Applications (Guest Editor Yu-Ning Zhang)


The present paper presents comparisons of the vortex identification between the omega method and the Q criterion based on the data of a classical flow. From the comparisons of the vortex structure together with the flow statistics, some important conclusions are drawn on the validity of the two methods, as follows. The omega method can identify various kinds of vortices with different intensities (e.g., the strong vortex, the medium vortex and the weak vortex). For the Q criterion, due to the subjective threshold selection, only the strong vortex with weak deformations could be identified. Finally, some emerging topics related with the advanced vortex identification methods are briefly discussed.

Key words

Vortex identification Galilean invariant Omega method 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



This work was supported by the Foundation of Key Laboratory of Condition Monitoring and Control for Power Plant Equipment (Ministry of Education), North China Electric Power University (Grant No. NDZG201807).


  1. [1]
    Zhang Y., Liu K., Xian H. et al. A review of methods for vortex identification in hydroturbines [J]. Renewable and Sustainable Energy Reviews, 2018, 81(Part 1): 1269–1285.CrossRefGoogle Scholar
  2. [2]
    Hunt J. C. R., Wray A. A., Moin P. Eddies, streams, and convergence zones in turbulent flows [C]. Studying Turbulence Using Numerical Simulation Databases, Proceedings of the 1988 Summer Program, San Francisco, USA, 1988, 193–208.Google Scholar
  3. [3]
    Jeong J., Hussain F. On the identification of a vortex [J]. Journal of Fluid Mechanics, 1995, 285: 69–94.MathSciNetCrossRefzbMATHGoogle Scholar
  4. [4]
    Dong X., Tian S., Liu C. Correlation analysis on volume vorticity and vortex in late boundary layer transition [J]. Physics of Fluids, 2018, 30(1): 014105.CrossRefGoogle Scholar
  5. [5]
    Dong X., Dong G., Liu C. Study on vorticity structures in late flow transition [J]. Physics of Fluids, 2018, 30(10): 104108.CrossRefGoogle Scholar
  6. [6]
    Zhang Y. N., Qiu X., Chen F. P. et al. A selected review of vortex identification methods with applications [J]. Journal of Hydrodynamics, 2018, 30(5): 767–779.CrossRefGoogle Scholar
  7. [7]
    Liu C., Wang Y. Q., Yang Y. et al. New omega vortex identification method [J]. Science China Physics, Mechanics and Astronomy, 2016, 59(8): 1–9.CrossRefGoogle Scholar
  8. [8]
    Dong X. R., Wang Y. Q., Chen X. P. et al. Determination of epsilon for omega vortex identification method [J]. Journal of Hydrodynamics, 2018, 30(4): 541–548.CrossRefGoogle Scholar
  9. [9]
    Liu C., Gao Y., Tian S. et al. Rortex a new vortex vector definition and vorticity tensor and vector decompositions [J]. Physics of Fluids, 2018, 30(3): 035103.CrossRefGoogle Scholar
  10. [10]
    Gao Y., Liu C. Rortex and comparison with eigenvaluebased vortex identification criteria [J]. Physics of Fluids, 2018, 30(8): 085107.CrossRefGoogle Scholar
  11. [11]
    Liu C., Gao Y. S., Dong X. R. et al. Third generation of vortex identification methods-Omega and Liutex/Rortex based systems [J]. Journal of Hydrodynamics, 2019, 31(2): Scholar
  12. [12]
    Li Y., Zhao S., Tagawa K. et al. Starting performance effect of a truncated-cone-shaped wind gathering device on small-scale straight-bladed vertical axis wind turbine [J]. Energy Conversion and Management, 2018, 167: 70–80.CrossRefGoogle Scholar
  13. [13]
    Li Y., Wang S., Liu Q. et al. Characteristics of ice accretions on blade of the straight-bladed vertical axis wind turbine rotating at low tip speed ratio [J]. Cold Regions Science and Technology, 2018, 145: 1–13.CrossRefGoogle Scholar
  14. [14]
    Li X., Jiang Z., Zhu Z. et al. Entropy generation analysis for the cavitating head-drop characteristic of a centrifugal pump [J]. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2018, 232(24): 4637–4646.Google Scholar
  15. [15]
    Li X., Gao P., Zhu Z. et al. Effect of the blade loading distribution on hydrodynamic performance of a centrifugal pump with cylindrical blades [J]. Journal of Mechanical Science and Technology, 2018, 32(3): 1161–1170.CrossRefGoogle Scholar
  16. [16]
    Liu Y., Tan L. Tip clearance on pressure fluctuation intensity and vortex characteristic of a mixed flow pump as turbine at pump mode [J]. Renewable energy, 2018, 129: 606–615.CrossRefGoogle Scholar
  17. [17]
    Hao Y., Tan L. Symmetrical and unsymmetrical tip clearances on cavitation performance and radial force of a mixed flow pump as turbine at pump mode [J]. Renewable Energy, 2018, 127: 368–376.CrossRefGoogle Scholar
  18. [18]
    Zhang Y., Zhang Y., Wu Y. A review of rotating stall in reversible pump turbine [J]. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 2017, 231(7): 1181–1204.Google Scholar
  19. [19]
    Li D., Wang H., Qin Y. et al. Numerical simulation of hysteresis characteristic in the hump region of a pump-turbine model [J]. Renewable energy, 2018, 115: 433–447.CrossRefGoogle Scholar
  20. [20]
    Li D., Wang H., Li Z. et al. Transient characteristics during the closure of guide vanes in a pump-turbine in pump mode [J]. Renewable Energy, 2018, 118: 973–983.CrossRefGoogle Scholar
  21. [21]
    Zhang Y., Chen T., Li J. et al. Experimental study of load variations on pressure fluctuations in a prototype reversible pump turbine in generating mode [J]. Journal of Fluids Engineering, 2017, 139(7): 074501.CrossRefGoogle Scholar
  22. [22]
    Zhang Y., Zheng X., Li J. et al. Experimental study on the vibrational performance and its physical origins of a prototype reversible pump turbine in the pumped hydro energy storage power station [J]. Renewable Energy, 2019, 130: 667–676.CrossRefGoogle Scholar
  23. [23]
    Zhang S., Li X., Hu B. et al. Numerical investigation of attached cavitating flow in thermo-sensitive fluid with special emphasis on thermal effect and shedding dynamics [J]. International Journal of Hydrogen Energy, 2019, 44(5): 3170–3184.CrossRefGoogle Scholar
  24. [24]
    Cui P., Zhang A. M., Wang S. et al. Ice breaking by a collapsing bubble [J]. Journal of Fluid Mechanics, 2018, 841: 287–309.CrossRefGoogle Scholar
  25. [25]
    Zhang A. M., Cui P., Cui J. et al. Experimental study on bubble dynamics subject to buoyancy [J]. Journal of Fluid Mechanics, 2015, 776: 137–160.CrossRefGoogle Scholar
  26. [26]
    Zhang Y., Zhang Y., Li S. Combination and simultaneous resonances of gas bubbles oscillating in liquids under dual-frequency acoustic excitation [J]. Ultrasonics Sonochemistry, 2017, 35(Part A): 431–439.CrossRefGoogle Scholar
  27. [27]
    Klapcsik K., Varga R., Hegedus F. Bi-parametric topology of subharmonics of an asymmetric bubble oscillator at high dissipation rate [J]. Nonlinear Dynamics, 2018 94(4): 2373–2389.CrossRefGoogle Scholar
  28. [38]
    Klapcsik K., Hegedus F. The effect of high viscosity on the evolution of the bifurcation set of a periodically excited gas bubble [J]. Chaos Solitons and Fractals, 2017, 104: 198–208.CrossRefGoogle Scholar
  29. [29]
    Zhang Y. N., Jiang Z. B., Yuan J. et al. Influences of bubble size distribution on propagation of acoustic waves in dilute polydisperse bubbly liquids [J]. Journal of Hydrodynamics, 2019, 31(1): 50–57.CrossRefGoogle Scholar
  30. [30]
    Zhang Y., Guo Z., Du X. Wave propagation in liquids with oscillating vapor-gas bubbles [J]. Applied Thermal Engineering, 2018, 133(3): 483–492.CrossRefGoogle Scholar
  31. [31]
    Zhang Y., Zhang Y., Qian Z. et al. A review of microscopic interactions between cavitation bubbles and particles in silt-laden flow [J]. Renewable and Sustainable Energy Reviews, 2016, 56: 303–318.CrossRefGoogle Scholar
  32. [32]
    Zhang Y., Chen F., Zhang Y. et al. Experimental investigations of interactions between a laser-induced cavitation bubble and a spherical particle [J]. Experimental Thermal and Fluid Science, 2018, 98: 645–661.CrossRefGoogle Scholar

Copyright information

© China Ship Scientific Research Center 2019

Authors and Affiliations

  • Yu-ning Zhang
    • 1
  • Xiao-yu Wang
    • 1
  • Yu-ning Zhang
    • 2
    • 3
  • Chaoqun Liu
    • 4
    Email author
  1. 1.Key Laboratory of Condition Monitoring and Control for Power Plant Equipment (Ministry of Education), School of Energy, Power and Mechanical EngineeringNorth China Electric Power UniversityBeijingChina
  2. 2.College of Mechanical and Transportation EngineeringChina University of Petroleum-BeijingBeijingChina
  3. 3.Beijing Key Laboratory of Process Fluid Filtration and SeparationChina University of Petroleum-BeijingBeijingChina
  4. 4.Department of MathematicsUniversity of Texas at ArlingtonArlingtonUSA

Personalised recommendations