the multi-sensor revolution: an integrated approach to advanced measurements in experimental hydraulics

Experimental hydraulics has undergone a paradigm shift from single-point measurements to integrated multi-sensor methodologies. this paper reviews the state-of-the-art in hydraulic measurement techniques, focusing on the synergistic use of advanced velocimetry, free-surface mapping, and two-phase flow characterization. the principles, characteristics, and applications of key technologies, including particle image velocimetry (piv), acoustic doppler velocimetry (adv), and advanced optical methods, are detailed. through a critical review of recent and verifiable literature, it is demonstrated how leading researchers combine these instruments to create comprehensive, high-fidelity datasets of complex phenomena such as bridge pier scour, vegetated channel flows, and energy dissipation on hydraulic structures. this integrated approach, linking subsurface turbulence dynamics to free-surface behavior and aeration characteristics, provides benchmark-quality data essential for validating next-generation computational fluid dynamics (cfd) models. the review concludes by highlighting future trends, including the integration of machine learning for data processing and the expansion of these techniques to field-scale applications. these advancements enable more accurate and sustainable hydraulic structure designs, enhancing engineering practice and public safety.