Enhancing Energy Efficiency in Propulsion Systems through Bio-Inspired Design

Recent research has explored the concept of improving propulsive efficiency through bio-inspired intermittent locomotion, specifically drawing inspiration from the swimming patterns of fish. The study, titled "Improving propulsive efficiency using bio-inspired intermittent locomotion," was authored by Tristan Aurégan, Mathilde Lemoine, Benjamin Thiria, and Sylvain Courrech du Pont. It was submitted to arXiv on August 26, 2024.

The researchers focused on a locomotion method known as burst-and-coast, which is commonly observed in smaller aquatic animals. This method contrasts with the continuous swimming seen in larger species and is associated with significant energy savings. The study measured the energy consumption of burst-and-coast cycles and compared it to traditional continuous rotation methods.

Key findings indicate that a substantial drag contrast between the active and passive phases of motion is crucial for achieving energy efficiency. This drag contrast can be realized using a folding propeller that opens and closes as it starts and stops rotating. The results demonstrated that this reconfigurable propeller could save up to 24% of the energy required for cruising at a constant speed.

Furthermore, the study established that intermittent motion is more efficient than continuous motion when the drag reduction during the coast phase exceeds 65%. For fish-like locomotion, this threshold appears to be closer to 30%. The authors provided a formal analogy to explain the differences between propeller propulsion and fish locomotion, highlighting the potential applications of these findings in designing more efficient propulsion systems.

The full paper can be accessed at arXiv:2408.14429.