The method to control the submarine horseshoe vortex by breaking the vortex core

Liu, Zhihua; Xiong, Ying; Tu, Chengxu

doi:10.1016/s1001-6058(14)60070-6

Cited by 9 publications

(2 citation statements)

References 3 publications

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“…In some conditions, the flow-induced noise can be described as the hydrodynamic noise. Recently, some phenomena of the flow-induced noise from underwater elastic structures similar to the submarines have been revealed, and the techniques of the flow control to reduce the hydrodynamic noise have been investigated [5,6]. However, these researches are only concerned in the optimization of the shape, which is probably not suitable for the submarines, because the optimization of the shape will squeeze some space of the submarines and is hardly to be carried out in practical engineering.As we know, the hydrodynamic noise of the submarines comes from the bow, the sail hull, the stern, and the propeller, which is mentioned earlier.…”

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“…One of the sources of the hydrodynamic noise is from the excitation by the horseshoe vortex. Liu et al have proposed the modified method of a vortex baffle to break the vortex core of the horseshoe vortex [6]. Since the horseshoe vortex is a giant vortex mass, from which the noise is in the low-frequency range, the control of the horseshoe vortex neglects the noise of high-frequency range.…”

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The Generation Mechanism of the Flow-Induced Noise from a Sail Hull on the Scaled Submarine Model

Liu

Shang

2018

Applied Sciences

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Featured Application: The results in this research can provide the design orientation for the flow control techniques to suppress the hydrodynamic noise from the sail hull. The results can also lay the foundation for the novel design of the sail hull with a low level of the flow-induced noise.Abstract: Flow-induced noise from the sail hull, which is induced by the horseshoe vortex, the boundary layer separation and the tail vortex shedding, is a significant problem for the underwater vehicles, while has not been adequately studied. We have performed simulations and experiments to reveal the noise generation mechanism from these flows using the scaled sail hull with part of a submarine body. The large eddy simulation and the wavenumber-frequency spectrum are adopted for simulations. The frequency ranges from 10 Hz to 2000 Hz. The simulation results show that the flow-induced noise with the frequency less than 500 Hz is mainly generated by the horseshoe vortex; the flow-induced noise because of the tail vortex shedding is mainly within the frequency of shedding vortex, which is 595 Hz in the study; the flow-induced noise caused by the boundary layer separation lies in the whole frequency range. Moreover, we have conducted the experiments in a gravity water tunnel, and the experimental results are in good accordance with the simulation results. The results can lay the foundation for the design of flow control devices to suppress and reduce the flow-induced noise from the sail hull.When the fluid flows around the submarine, two kinds of noises will be generated. The turbulent fluctuation pressure in the flow radiates a noise, which is called the flow noise. The elastic shell of the submarine is excited by the turbulent fluctuation pressure, and radiates the flow-induced noise. The hydrodynamic noise is the summation of the flow noise and the flow-induced noise. Since the sound pressure level of the flow noise is much lower than that of the flow-induced noise, the flow noise is usually negligible. In some conditions, the flow-induced noise can be described as the hydrodynamic noise. Recently, some phenomena of the flow-induced noise from underwater elastic structures similar to the submarines have been revealed, and the techniques of the flow control to reduce the hydrodynamic noise have been investigated [5,6]. However, these researches are only concerned in the optimization of the shape, which is probably not suitable for the submarines, because the optimization of the shape will squeeze some space of the submarines and is hardly to be carried out in practical engineering.As we know, the hydrodynamic noise of the submarines comes from the bow, the sail hull, the stern, and the propeller, which is mentioned earlier. The noise generation mechanism of the submarine is complicated because of its complex structure. The previous studies on the flow-induced noise of the submarines stem from the cylinder for its simple structure [7], and some analytical equations are obtained. However, the bow, the sail hull and the stern o...

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