Propeller cavity bursting,triggered by the sharp hull wake,can significantly increase broadband noise.However,its complex multiscale nature presents substantial challenges for numerical simulations,limiting the predic...Propeller cavity bursting,triggered by the sharp hull wake,can significantly increase broadband noise.However,its complex multiscale nature presents substantial challenges for numerical simulations,limiting the prediction accuracy for propeller cavitation noise to only the first few blade-passing frequencies.To overcome this limitation,this study explores the potential of a novel Euler-Lagrange hybrid model for simulating cavity bursting and the resulting broadband noise.Focused on a benchmark test case of the INSEAN E779A propeller,the numerical results effectively reproduce the measured cavity bursting and its associated broadband pressure fluctuations,providing valuable insights for realistic simulations of propeller cavitation noise.展开更多
The cavitation has received considerable attention for decades because of its negative influence on the performance and the safety of the hydraulic machinery.In this study,a large eddy simulation is carried out to num...The cavitation has received considerable attention for decades because of its negative influence on the performance and the safety of the hydraulic machinery.In this study,a large eddy simulation is carried out to numerically investigate the unsteady cavitating flow around a trailing-truncated NACA 0009 hydrofoil for determining the underlying physical mechanisms.Two types of cavitation morphologies are identified:The large-scale bubble cluster and the von Kármán vortex cavity,named as the cloud cavitation and the wake vortex cavitation,respectively.It is shown that the velocity profiles obtained over the hydrofoil suction surface are in good agreement with the experimental data,indicating the accuracy of the current simulation.The dynamic evolution of the sheet/cloud cavity is also well reproduced,covering the sheet cavity breakup,the sheet/cloud transformation,and the collapse of the cloudy bubble cluster.The wake-vortex cavitation is caused by the blunt geometry at the hydrofoil trailing edge,where pairs of vortex cavities are induced.Both the cloud and vortex cavities significantly affect the lift oscillation,which makes it difficult to decompose the components.The fundamental shedding mechanisms of the wake vortex cavitation are discussed based on the finite-time Lyapunov exponent field.Specifically,the suction-side bubble grows and squeezes the giant pressure bubble away from the trailing edge.After the pressure bubble detaches,a new counterclockwise vortex or a new bubble appears at the pressure side,thus lifting the ridge towards the suction trailing edge and generating a strong vortex eye that pinches off the trailing portion of the suction-side bubble.展开更多
基金supported by the National Natural Science Foundation of China(Project Nos.52479085 and 123B2032).
文摘Propeller cavity bursting,triggered by the sharp hull wake,can significantly increase broadband noise.However,its complex multiscale nature presents substantial challenges for numerical simulations,limiting the prediction accuracy for propeller cavitation noise to only the first few blade-passing frequencies.To overcome this limitation,this study explores the potential of a novel Euler-Lagrange hybrid model for simulating cavity bursting and the resulting broadband noise.Focused on a benchmark test case of the INSEAN E779A propeller,the numerical results effectively reproduce the measured cavity bursting and its associated broadband pressure fluctuations,providing valuable insights for realistic simulations of propeller cavitation noise.
基金This work was supported by the University of Padua Project of Investigation of Passive Suppression of Unsteady Cloud Cavitation(Grant No.2020DII142)The authors acknowledge the Italian CINECA for Providing the Computational Resources(Grant No.HP10CZ82QS)。
文摘The cavitation has received considerable attention for decades because of its negative influence on the performance and the safety of the hydraulic machinery.In this study,a large eddy simulation is carried out to numerically investigate the unsteady cavitating flow around a trailing-truncated NACA 0009 hydrofoil for determining the underlying physical mechanisms.Two types of cavitation morphologies are identified:The large-scale bubble cluster and the von Kármán vortex cavity,named as the cloud cavitation and the wake vortex cavitation,respectively.It is shown that the velocity profiles obtained over the hydrofoil suction surface are in good agreement with the experimental data,indicating the accuracy of the current simulation.The dynamic evolution of the sheet/cloud cavity is also well reproduced,covering the sheet cavity breakup,the sheet/cloud transformation,and the collapse of the cloudy bubble cluster.The wake-vortex cavitation is caused by the blunt geometry at the hydrofoil trailing edge,where pairs of vortex cavities are induced.Both the cloud and vortex cavities significantly affect the lift oscillation,which makes it difficult to decompose the components.The fundamental shedding mechanisms of the wake vortex cavitation are discussed based on the finite-time Lyapunov exponent field.Specifically,the suction-side bubble grows and squeezes the giant pressure bubble away from the trailing edge.After the pressure bubble detaches,a new counterclockwise vortex or a new bubble appears at the pressure side,thus lifting the ridge towards the suction trailing edge and generating a strong vortex eye that pinches off the trailing portion of the suction-side bubble.
