# Contrasting Flexible and Rigid Bioinspired Flapping Hydrofoils for Suspended Particles Discharge in Raceway Aquaculture

## TL;DR

This study compares flexible and rigid flapping hydrofoils to see how they affect the discharge of suspended particles in aquaculture systems.

## Contribution

The study introduces a bioinspired flexible hydrofoil design that improves particle discharge characteristics through delayed vortex shedding.

## Key findings

- Flexible hydrofoils with 0.05 GPa elastic modulus increased particle escape rates by 3–4% during discharge.
- Flexible hydrofoils showed greater surface deformation and prolonged high flow velocities compared to rigid ones.
- Both flexible and rigid hydrofoils achieved nearly identical maximum discharge efficiency at around 97.8%.

## Abstract

To investigate the impact of flexible versus rigid bioinspired flapping hydrofoils on the discharge characteristics of suspended particles in raceway aquaculture, this study established a two-way fluid–structure coupling model of a flapping hydrofoil device based on ANSYS Fluent and Transient Structural modules. The research compares the discharge characteristics of hydrofoils with different elastic moduli. The results show that, within a certain range of elastic moduli adjustment, flexible bioinspired hydrofoils exhibit greater surface deformation compared to rigid ones, effectively delaying tail vortex shedding and extending its duration, thus prolonging the range of high flow velocities. During the middle stage of discharge, the escape rate of suspended particles under the influence of flexible bioinspired hydrofoils with 0.05 GPa elastic modulus was 3–4% higher than that of rigid hydrofoils. However, in terms of achieving maximum discharge efficiency and effectiveness, both reached approximately 97.8% with little difference between them. This study highlights the bioinspired principles in hydrofoil design and provides a reference for optimizing flexible hydrofoil discharge characteristics in future research.