A review of particle image velocimetry in fish-inspired biomimetic propulsion

Abstract

Fish demonstrate exceptional swimming performance and energy utilization, inspiring the development of fish-inspired biomimetic propulsion to enhance underwater unmanned vehicles (UUVs) design. Particle image velocimetry (PIV) is a powerful experimental tool that enables detailed insights into swimming flow mechanisms. This review outlines PIV techniques and data analysis methods applied to fish-inspired biomimetic propulsion research. Relevant studies are categorized into two main areas: biological experiments on living fish and biomimetic implementations. PIV's role in revealing wake characteristics in various swimming modes in living fish studies is highlighted. Biomimetic experiments are divided into foil systems, which focus on assessing the effects of different factors on wake structure, thrust, and efficiency, and whole-body bionic fish systems, which highlight the role of the caudal fin and multi-fin interactions. This review highlights that PIV's ability to reveal complex vortex structures enhances our understanding of efficient swimming, bridging the gap between biomimetic propulsion and living fish, and offering a valuable framework for advancing fish-inspired UUV design. • Review PIV studies on fish and biomimetic propulsion, linking natural swimming with engineering design. • Advances in planar, multi-plane, and volumetric PIV for biomimetic propulsion applications are reviewed. • PIV-based flow analysis methods are summarized, including decomposition, advanced modeling, and uncertainty quantification. • Vortex dynamics, wake structures, and fin-body coordination are summarized across fish swimming modes. • Comparative PIV studies on foils and robotic fish, show how geometry, flexibility, and kinematics affect propulsion.