Experimental Approach on Free-swimming of Biomimetic Helical Swimmer under Different Helical Tail Parameters

Design and fabrication of intelligent micro devices for various applications such as medical investigation, industrial implementation, etc. is being considered as an effective field of study recently. One of these devices is Biomimetic swimmer micro-robot with helical propulsive tail which swims in Low Reynolds condition and it has a great impact on medical applications. Design and optimization of physical and geometrical of these swimming robots in order to achieve good performances is an important issue apparently. In this study, Biomimetic helical swimmer which propels itself freely in a rectangular channel containing high viscosity fluid is addressed appropriately. Physical and geometrical parameters of the swimmer propulsion element including wavelength, length of the helical tail, and spinal propulsive frequency are subjected to variable range values to investigate the effect of these parameters on the forward approaching velocity. In order to predict and to model the forward approaching performances of swimmer, Resistive Force Theory (RFT) and Slender Body Theory (SBT) are also in use for comparisons of the results. To validate these theoretical results, experiments were carried out to evaluate the forward approaching velocity of the swimmer in silicone oil. Experimental results confirm to the theoretical values predicted by SBT. It is found that, in the large helix length and large spinal propulsive frequency, theoretical results are matched to experimental data satisfactory. Results indicate that with increasing helical length and spinal propulsive frequency, forward approaching velocity increases.