Geometry optimization of helical swimming at low Reynolds number

This paper aims to improve magnetic helical swimming varying the cross-section geometry and considering a conical geometry for helical robot. Both parameters have not been extensively studied in the literature. The conical helix is generated when the helix radial pitch varies constantly and due to that, it could be used in delivery tasks of big-sized millimetric objects. To conceive the whole study, experimentation, and finite-element-method (FEM) simulations are performed in order to corroborate the experimental data in the literature. The influence on the propulsion of the helix cross-section geometry in a cylindrical helix, and the number of turns in a conical helix was demonstrated. Results show that helices with triangular cross-sections provide better propulsion than circular ones, these latter widely used in various micro-and nano-swimmer designs in literature. This result could change the way that helical swimmers are manufactured today. Besides, conical helices with 1-turn and 1.5-turn have shown better performances than multi-turn ones in terms of speed and propulsion force. From this part of the study, the main contribution has been the novel design proposed for delivery tasks.