Models of the turning and fast-start swimming dynamics of aquatic vertebrates

ABSTRACT

Two models for unpowered and powered turns and C-type fast-starts were developed and applied to four different manoeuvres: unpowered turns by a streamlined fish (yellowfin tuna Thunnus albacares), powered turns by an unstreamlined fish (boxfish Ostracion meleagris), fast-starts (sticklebacks Gasterosteus spp.) and a manoeuvre by a steller sea lion Eumetopias jubatus deploying control surfaces (flippers). The velocity at the end of manoeuvres (terminal velocity) was employed as the 'benchmark variable' for comparisons of predicted and actual performance. Good agreement was found in all cases. A log–log plot of available experimental data for turning radius v. mass shows that turning radius scales to the 0·37 power of mass (r²= 0·73), close to the predicted value of 0·33. Recent interests in highly manoeuvrable aquatic vertebrates as biomimetic models for automated underwater vehicles adds to the practical utility of the models presented here.