Neural Operators for Immersed-Boundary Soft Swimmers Locomotion
This work addresses the high computational cost of high-fidelity immersed boundary simulations for fluid–structure interaction in soft-bodied swimmers, which hinders repeated evaluations required for design optimization and control. To overcome this limitation, the authors propose a neural operator-based surrogate model trained on regular-grid data generated from adaptive fluid–structure interaction simulations. Conditioned on swimmer geometry and Reynolds number, the model enables temporally resolved prediction of unsteady flow fields around two- and three-dimensional eel-like swimmers. This study presents the first neural surrogate capable of full-field, multi-physics prediction—including velocity, vorticity, and pressure—for moving-boundary swimmers, demonstrating strong generalization across geometries and parameters. The two-dimensional model achieves a mean relative L² error of 3.51% on five extrapolated high-Reynolds-number trajectories, while the three-dimensional model yields errors of 3.44% (velocity), 5.58% (vorticity), and 19.2% (pressure) on interpolated trajectories.