Research on swimming hydrodynamics based on a three‐dimensional high‐precision fish model

Abstract Fish swimming hydrodynamics serves as a critical foundation for aquatic ecological conservation, with recent research extending from 2D to 3D perspectives. This study employs 3D high‐fidelity modeling with dynamic mesh technology to investigate how cylindrical obstacles at varying positions affect Carassius auratus locomotion. Analysis of nine configurations reveals bidirectional flow interactions between fish and cylinders, with cylinder wake influence persisting at 1–2 times the total length intervals but diminishing at 3times. Compared with swimming in uniform flow, the mechanical benefit of C. auratus located 2 times the total length directly behind the cylinder is the largest, and its value reaches 4.19 times. Wavelet analysis of 30‐cycle mechanical data demonstrates closer intervals enhance benefit magnitude, whereas greater distances accelerate benefit realization. These 3D computational findings corroborate 2D studies while providing new spatial interaction insights, offering theoretical foundations for fish conservation strategies related to hydraulic structures.