Experimental study of unsteady evolution characteristics of ventilated air mass on the cylinder surface

Qu, Zhaoyu; Yang, Nana; Ma, Guihui; Yao, Xiongliang; Chen, Yingyu

doi:10.1016/j.oceaneng.2022.112462

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…To investigate the evolution characteristics of the surface ventilated cavity on an underwater vehicle, the unsteady ventilated cavity flow on the surface of the underwater vehicle was studied experimentally. This study has achieved good repeatability in previous experimental studies (Qu et al 2022). In these tests, the initial pressure P in of the pressure tank was 150 kPa and the gas pressure P atm above the water surface of the test tank remained at 10 kPa.…”

Section: Evolution Of Ventilated Cavitysupporting

confidence: 64%

“…Javadpour et al (2017) and Sun et al (2020) experimentally studied the evolution characteristics of ventilated cavities and analysed the gas entrainment mechanism, finding that an increase in the ventilation rate can improve the stability of the cavity. Qu et al (2022) experimentally investigated the evolution characteristics of the ventilated cavity of a vertical moving vehicle, and found that the size of the ventilated cavity grows more rapidly at a low cavitation number. Huang et al (2022) further explored the influence of the Froude number on the cavity behaviour, and found that unstable cavity flows appeared at high Froude numbers alongside dynamic behaviours such as cavity shedding.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and numerical study on unsteady entrainment behaviour of ventilated air mass in underwater vehicles

Qu,

Yang,

Yao

et al. 2023

Fluid Dyn. Res.

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The hydrodynamic characteristics of underwater vehicles are significantly affected by the ventilated cavity covered by the vehicle surface. In this paper, the unsteady flow characteristics of this ventilated cavity are studied using experimental and numerical methods, and the unsteady entrainment behaviour of the ventilated air mass is emphasised. The flow pattern of the ventilated air mass is recorded using a high-speed camera. The large eddy simulation turbulence model is employed for the numerical simulations, and a good agreement is observed between the experimental and numerical results. In the early stage of the formation of the ventilated air mass, the internal structure exhibits a symmetric kidney vortex system, while the ventilated cavity below the vent hole has a continuous hairpin vortex structure. The ventilated air mass experiences a growth stage, an entrainment stage, and a shedding stage. The entrainment behaviour enables the ventilated air mass to quickly fill the ventilated cavity and modifies the surface pressure distribution of the vehicle. As the cavitation number decreases, the radial size of the ventilated cavity increases, and the contact area between the cavity and the water body increases, thus enhancing the vertical drag coefficient of the vehicle.

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Section: Evolution Of Ventilated Cavitysupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Experimental and numerical study on unsteady entrainment behaviour of ventilated air mass in underwater vehicles

Qu,

Yang,

Yao

et al. 2023

Fluid Dyn. Res.

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“…In a ventilated cavity flow, entrainment and vortex are the problems that need to be solved [25][26][27][28]. Moudjed et al [29] changed the vortex structure by adding obstacles and found that the use of large obstacles can easily lead to gas entrainment with a lower suction velocity.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Motion Characteristics of Cavity Attached to the Tail of Underwater Vehicle

Yao

et al. 2023

JMSE

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The formation and development of an attached cavity at the tail of an underwater moving vehicle involves a complex multiphase flow, which determines the load characteristics and motion stability of the vehicle. In this study, an experimental method was used to explore the formation process and motion characteristics of the cavity at the tail of the vehicle, and a pressure sensor installed at the tail of the model was used to establish the relationship between the evolution of the tail attachment cavity and transient pressure. The study found that the process of pulling and breaking the attached cavity was accompanied by the generation of bidirectional jets, and reducing the cavitation number could weaken the occurrence of jet impact. When the ventilation flow reaches the critical value Q¯in = 1.28, the cavity pulsates. In addition, increasing the ventilation flow does not increase the size of the tail cavity, and the length of the cavity at the closure increases with the decrease of the cavitation number.

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Numerical study on the pulsation characteristics of tail cavities under vertical launching conditions

Ren,

Wang,

Cheng

et al. 2024

Ocean Engineering

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Experimental study of unsteady evolution characteristics of ventilated air mass on the cylinder surface

Cited by 5 publications

References 21 publications

Experimental and numerical study on unsteady entrainment behaviour of ventilated air mass in underwater vehicles

Experimental and numerical study on unsteady entrainment behaviour of ventilated air mass in underwater vehicles

Experimental Study on Motion Characteristics of Cavity Attached to the Tail of Underwater Vehicle

Numerical study on the pulsation characteristics of tail cavities under vertical launching conditions

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