A COMPUTATIONAL FLUID-DYNAMICS STUDY OF TADPOLE SWIMMING

The hydrodynamics and undulating propulsion of tadpoles were studied u sing a newly developed two-dimensional computational fluid dynamics (C FD) modeling method. The mechanism of thrust generation associated wit h the how patterns during swimming is discussed. Our CFD analysis show s that the kinematics of tadpoles is specifically matched to their spe cial shape and produces a jet-stream propulsion with high propulsive e fficiency, as high as that achieved by teleost fishes. Investigation o f the effect of Reynolds number indicates that the Froude efficiency i ncreases with increasing Reynolds number with no ceiling in generating the jet-stream propulsion. Further studies using tadpole- and fish-sh aped models with hindlimbs added to their body profiles reveal that th e tadpole shape - a globose head with a tapered tail and hindlimbs at the base of the tail - allows tadpoles, but not fish, to develop hindl imbs with very little handicap on propulsion. The shapes and kinematic s of tadpoles appear to be specially adapted to the requirement of the se organisms to transform into frogs.