# Forces and energetics of intermittent swimming

## TL;DR

This study investigates the physics and energetics of intermittent swimming, revealing that thrust and power scale linearly with duty cycle and that intermittent motions can be more energy-efficient than continuous swimming.

## Contribution

It provides experimental evidence that intermittent swimming maintains similar vortex structures and can be energetically advantageous, with implications for biological and robotic swimming strategies.

## Key findings

- Thrust and power scale linearly with duty cycle.
- Vortical structures are unchanged across duty cycles.
- Intermittent swimming can be more energy-efficient than continuous swimming.

## Abstract

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by PIV flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.