Vortex interactions of two burst-and-coast swimmers in a side-by-side arrangement

Both schooling behavior and burst-and-coast gait could improve fish swimming performance. The extent to which fish can improve their swimming performance by combining these two strategies is still unknown. By examining two self-propelled pitching foils positioned side-by-side at different duty cycles (DC), we examine swimming speed and cost of transport efficiency (CoT) using the open-source immersed boundary software IBAMR. We find that a stable schooling formation can only be maintained if both foils employ similar and moderate DC values. In these cases, vortex interactions increase foils' lateral movements, but not their swimming speed or efficiency. Additionally, we examine vortex interactions in both schooling and fission scenarios (which are determined by DC). The research provides useful insights into fish behavior and valuable information for designing bio-inspired underwater robots.

Automated summary

Both schooling behavior and burst-and-coast gait improve fish swimming performance, but the combined effect of these strategies is still unknown. Using the IBAMR software, we examine swimming speed and cost of transport efficiency by studying two pitching foils with different duty cycles. The findings suggest that stable schooling formation can only be maintained with similar and moderate duty cycles, which increase lateral movements but not swimming speed or efficiency. This research provides insights into fish behavior and valuable information for designing bio-inspired underwater robots.