Numerical study of propulsion mechanism for oscillating rigid and flexible tuna-tails

L. Yang, Y. M. Su, Q. Xiao

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16 Citations (Scopus)


Numerical study on the unsteady hydrodynamic characteristics of oscillating rigid and flexible tuna-tails in viscous flow-field is performed. Investigations are conducted using Reynolds-Averaged Navier-Stokes (RANS) equations with a moving adaptive mesh. The effect of swimming speed, flapping amplitude, frequency and flexure amplitude on the propulsion performance of the rigid and flexible tuna-tails are investigated. Computational results reveal that a pair of leading edge vortices develop along the tail surface as it undergoes an oscillating motion. The propulsive efficiency has a strong correlation with various locomotive parameters. Peak propulsive efficiency can be obtained by adjusting these parameters. Particularly, when input power coefficient is less than 2.8, the rigid tail generates larger thrust force and higher propulsive efficiency than flexible tail. However, when input power coefficient is larger than 2.8, flexible tail is superior to rigid tail.

Original languageEnglish
Pages (from-to)406-417
Number of pages12
JournalJournal of Bionic Engineering
Issue number4
Publication statusPublished - Dec 2011


  • hydromechanics
  • swimming propulsion
  • tuna-tail
  • fin
  • performance
  • RANS
  • hydrodynamic characteristics
  • propulsion mechanism
  • viscous flow-fields
  • numerical study
  • oscillating
  • rigid
  • flexible

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