Research on Coupled Bionic Design and Validation of Autonomous Underwater Vehicle Based on Mako Shark Morphological Characteristics

This study is based on the theory and methodology of the coupled extension analysis method, utilizing the morphological characteristics of the mako shark as the bionic prototype to develop a coupled bionic design scheme for an autonomous underwater vehicle (AUV). The objective is to reduce hydrodynamic drag during underwater operation, enhance propulsive efficiency, and thereby extend operational duration and range. Initially, data on AUV morphological design standards were collected. The bionic prototype was selected from ichthyological databases through comparative biological data analysis. A 3-D model of the prototype’s overall morphology was created via reverse engineering and quantitatively analyzed using the 3-D shape error measurement method. Morphological characteristic curves were extracted from the 3-D model and smoothed using polynomial fitting. Subsequently, the coupled extension analysis method and a comprehensive coupling index evaluation function were employed to analyze the coupling bionic feature vectors and eigenvalues between the AUV and the prototype morphology. Based on this, a coupled extension matrix model was constructed to guide the coupled bionic design of the AUV using the mako shark’s morphological features. Finally, the design scheme was validated through fluid simulation using computational fluid dynamics and experimental testing methods. Under various angles of attack, the drag force of the coupled bionic design scheme for the AUV exhibited a clear increase in gradient with rising flow velocity, showing a smooth growth trend. The drag coefficient demonstrated a consistent downward trend, with its gradient converging distinctly, reflecting the scientific rationality of the coupled bionic design scheme based on the mako shark’s morphological characteristics. Results from both fluid simulations and experimental tests confirm the soundness of this design scheme. The research methodology and validation process are scientifically rigorous. Further comparative data and verification indicate that the coupled bionic design scheme achieves significantly better drag-reduction performance across different angles of attack and speeds compared to the Blue Spirit-300 AUV, highlighting the engineering significance of this study.