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国际流体力学研究期刊
ESCI SJR: 0.206 SNIP: 0.446 CiteScore™: 0.5

ISSN 打印: 2152-5102
ISSN 在线: 2152-5110

国际流体力学研究期刊

DOI: 10.1615/InterJFluidMechRes.v38.i6.90
pages 565-571

Robo-Linked Purcell's Swimmer

M. Siva Kumar
Department of Physics, Indian School Muscat, The Sultanate of Oman
P. Philominathan
Department of Physics, AVVM Sri Pushpam College Tanjore , India

ABSTRACT

EM Purcell proposed three-linked swimmer 60 years ago as a hypothetical creature capable of swimming in highly viscous fluid. We have constructed a scaled model of this swimmer to investigate reciprocal and non-reciprocal swimming motion. The links were programmatically rotated by the interactive servomotors controlled by a microcomputer. Reciprocal motion of the links produced no net displacement illustrating the effect of scallop theorem. Experiments on non-reciprocal motion captured very important property suggested by theories: small stroke angles cause forward swimming and large stroke angles backward. We have measured non-dimensional displacement per cycle and compared with the theoretical predictions and found consistent. Surprisingly, in low-frequency region, flapping frequency of the links also play a role in determining swimming direction. The low-Reynolds number swimming is characterised by Stokes equation which is linear and time-independent. But frequency dependence in low-frequency region shows the breakdown of Stokes law with inertia.