2025
Yin, Tingyun; Pavesi, Giorgio
Several compressible computational fluid dynamics methods applied to transient sheet/cloud cavitation Journal Article
In: Physics of Fluids, vol. 37, iss. 2, 2025, ISSN: 10897666.
Abstract | Links | BibTeX | Tags: Cavitation, Cloud cavitation, Sheet Cavitation
@article{Yin2025b,
title = {Several compressible computational fluid dynamics methods applied to transient sheet/cloud cavitation},
author = {Tingyun Yin and Giorgio Pavesi},
doi = {10.1063/5.0252333},
issn = {10897666},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Physics of Fluids},
volume = {37},
issue = {2},
publisher = {American Institute of Physics},
abstract = {This paper introduces several compressible computational fluid dynamics (CFD) methods and assesses their ability to simulate typical sheet-to-cloud cavitating flow around a hydrofoil. More precisely, the Tait equation of state is used to describe the density of water, while the ideal gas equation of state is used to model the density of vapor. The first method assumes that the cavitation is a multiphase flow with isothermal conditions, meaning that it exhibits isothermal compressibility. Based on the first method, the second and third methods take into account the thermal energy and total energy equations, respectively, i.e., the thermal energy compressibility and the total energy compressibility. An incompressible simulation is also performed for the comparison. The results show that all of the strategies successfully replicate the periodic breakup of the sheet cavity and the formation of the cloud cavity. The predicted frequency of cavity shedding using compressible methods is higher than that using the incompressible method. In addition, all the CFD simulations confirm that the disturbance moving upward in the sheet cavity is actually a condensation shock. The overpressure resulting from the collapse of the cavity can be captured using three compressible approaches. The boundary layer and time-averaged hydrofoil pressure coefficient are compared and analyzed, revealing a negligible difference among the three compressible simulation results.},
key = {Cavitation, sheet cloud},
keywords = {Cavitation, Cloud cavitation, Sheet Cavitation},
pubstate = {published},
tppubtype = {article}
}
This paper introduces several compressible computational fluid dynamics (CFD) methods and assesses their ability to simulate typical sheet-to-cloud cavitating flow around a hydrofoil. More precisely, the Tait equation of state is used to describe the density of water, while the ideal gas equation of state is used to model the density of vapor. The first method assumes that the cavitation is a multiphase flow with isothermal conditions, meaning that it exhibits isothermal compressibility. Based on the first method, the second and third methods take into account the thermal energy and total energy equations, respectively, i.e., the thermal energy compressibility and the total energy compressibility. An incompressible simulation is also performed for the comparison. The results show that all of the strategies successfully replicate the periodic breakup of the sheet cavity and the formation of the cloud cavity. The predicted frequency of cavity shedding using compressible methods is higher than that using the incompressible method. In addition, all the CFD simulations confirm that the disturbance moving upward in the sheet cavity is actually a condensation shock. The overpressure resulting from the collapse of the cavity can be captured using three compressible approaches. The boundary layer and time-averaged hydrofoil pressure coefficient are compared and analyzed, revealing a negligible difference among the three compressible simulation results.
2022
Yin, Ting; Pavesi, Giorgio; Pei, Ji; Yuan, Shou; Gan, Xing
Large eddy simulation of cloud cavitation and wake vortex cavitation around a trailing-truncated hydrofoil Journal Article
In: Journal of Hydrodynamics, vol. 34, iss. 5, pp. 893-903, 2022, ISSN: 18780342.
Abstract | Links | BibTeX | Tags: Cloud cavitation, large eddy simulation, trailing-truncated hydrofoil, wake vortex cavitation
@article{YinPavesi2022-03,
title = {Large eddy simulation of cloud cavitation and wake vortex cavitation around a trailing-truncated hydrofoil},
author = {Ting Yin and Giorgio Pavesi and Ji Pei and Shou Yuan and Xing Gan},
doi = {10.1007/s42241-022-0073-9},
issn = {18780342},
year = {2022},
date = {2022-01-01},
journal = {Journal of Hydrodynamics},
volume = {34},
issue = {5},
pages = {893-903},
publisher = {Springer},
abstract = {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.},
keywords = {Cloud cavitation, large eddy simulation, trailing-truncated hydrofoil, wake vortex cavitation},
pubstate = {published},
tppubtype = {article}
}
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.
