Active water injection combined with barchan dune vortex generators for cavitating flow noise suppression

• Published in: Ocean engineering 2024-11, Vol.312, p.119123, Article 119123
• Main Authors: Li, Zhijian, Wang, Wei, Ji, Xiang, Wang, Yun, Wang, Xiaofang
• Format: Article
• Language: English
• Subjects: Barchan dune; Cavitating flow; Compound flow control; Mass transfer; Vortex generators; Water injection
• ISSN: 0029-8018
• DOI: 10.1016/j.oceaneng.2024.119123

This study proposes a barchan dune-shaped vortex generator (BDVG) combined with active water injection to form a compound flow control technology for suppressing cavitation and reducing underwater noise. A NACA66 hydrofoil is simulated using large eddy simulation and the acoustic analogy method, showing good agreement with experimental results. Key findings include a 91.07% reduction in cavitation volume and decreases in monopole and dipole noise by 9.25 dB and 5.23 dB, respectively. Both the passive BDVG and the compound method significantly improve the hydrofoil's lift-to-drag ratio. The cavitation dynamics have changed greatly, showing hindered development, premature destabilization, and fragmentation of attached cavitation. Further analysis reveals that the compound method transforms a simple water-vapor transfer pattern into a complex, condensation-dominated state, effectively suppressing cavitation. The study finds that the original single free cloud collapse becomes an incomplete, asynchronous collapse of scattered clouds, with local collapse and rebound of scattered cloud clusters on hydrofoils occurring more frequently. These features significantly weaken the non-uniform velocity characteristics of the overall cavitation volume, effectively suppressing cavitation noise. Finally, a simplified model is developed to predict monopole noise sound pressure, with a prediction error of sound pressure at the dominant frequency less than 0.3 dB. •Innovative combination of passive and active flow control strategies to mitigate cavitation and reduce associated noise•Revealing the reduction mechanisms of noise based on flow dynamics characteristics.•Development of a simplified model for predicting monopole noise.