Aquatic propulsion and fluid dynamics of living and robotic frogsĀ 


Swimmers use two general strategies: steady-speed (e.g. fish) versus unsteady ‘burst-and-glide’ swimming (e.g. frogs).  While scientists have studied fish hydrodynamics to improve speed and efficiency in robots, frog propulsion has largely been neglected.  Unlike fish, frogs have evolutionarily co-opted powerful jumping muscles to generate large fluid forces as they kick.  Additionally, theory predicts that certain frogs amplify thrust via a central water jet as the legs whip together during kicking.  We aim to quantify fluid dynamics on living and robotic frogs to test this ‘central jet theory’ and to discover additional unsteady fluid mechanisms that enhance swimming performance.


GAL, JULIANNA M., and R. W. Blake. "Biomechanics of frog swimming: II. Mechanics of the limb-beat cycle in Hymenochirus Boettgeri." Journal of experimental biology 138.1 (1988): 413-429.


Nauwelaerts, Sandra, Eize J. Stamhuis, and Peter Aerts. "Propulsive force calculations in swimming frogs I. A momentum–impulse approach." Journal of experimental biology 208.8 (2005): 1435-1443.


Johansson, L. Christoffer, and George V. Lauder. "Hydrodynamics of surface swimming in leopard frogs (Rana pipiens)." Journal of experimental biology 207.22 (2004): 3945-3958.  


Richards, Christopher T. "Kinematics and hydrodynamics analysis of swimming anurans reveals striking inter-specific differences in the mechanism for producing thrust." The Journal of experimental biology 213.4 (2010): 621-634.

Biological Areas:



Animal disease, health and welfare