On the Strouhal Number of Fish Undulatory Swimming: A Simple Predictive Analysis Based on the Buckling of Columns

On the Strouhal Number of Fish Undulatory Swimming: A Simple Predictive Analysis Based on the Buckling of Columns

J.G. Cervantes F. Méndez F.J. Solorio 

Faculty of Engineering, National University of Mexico, Mexico

31 January 2007
| Citation



An analogy between fi sh undulatory swimming and the buckling of columns is presented and discussed. The most important aspects of the undulatory swimming of a fi sh, from the mechanical point of view, are described. The buckling response of solid and fl uid columns and its mathematical modelling are summarized and applied to a swimming fi sh, as an analogue of buckling columns. The predictable Strouhal number for a buckling fi sh agrees well with the apparently universal experimental value observed by numerous investigators of fi sh undulatory swimming.


buckling of columns, fi sh undulatory swimming, fl uid columns, hydrodynamic foils, solid columns, Strouhal number.


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