Numerical study on evolution of axisymmetric natural supercavitation influenced by turbulent drag-reducing additives

Jiang, Chenxing; Shuai, Zhi-Jun; Zhang, Xiang-Yuan; Li, Wanyou; Li, Feng‐Chen

doi:10.1016/j.applthermaleng.2016.07.040

Cited by 17 publications

(5 citation statements)

References 14 publications

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“…The method is capable of accurately simulating the internal flow characteristics and the geometric shape of the cavity, producing results that are consistent with experimental results. Jiang et al [27] simulated the geometric shape of a ventilated cavity and the submarine drag characteristics, achieving agreement with experimental findings. Furthermore, they proposed a resistance reduction scheme based on the simulation results.…”

Section: Introductionmentioning

confidence: 58%

Numerical Investigation on the Ventilated Supercavity around a Body under Free Surface Effect

Zhi

Jin

Huang

et al. 2023

JMSE

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Reducing vessel resistance by using ventilated cavities has been a highly researched topic in the marine industry. There is limited literature on ventilated supercavities near the free surface, which indicates that their dynamic behavior is more complex than conventional ventilated cavities due to the effect of the free surface. This paper employs numerical simulations to study the dynamic behavior of the ventilated supercavity, taking into account the effect of the free surface. Numerical simulations can predict gas leakage behaviors, cavity geometry, and internal flow structures. The influence of the free surface shortens the length of the ventilated cavity and increases the diameter. The presence of the free surface mainly changes the vertical velocity distribution between the free surface and the cavity. The results show that there are two typical gas leakage mechanisms under different immersion depths: twin-vortex tube leakage mode and re-entrant jet leakage mode. The internal flow field of ventilated supercavity is classified into three regions: the internal boundary layer, the ventilation influence region, and the reverse flow region. As the distance between the free surface and the ventilated supercavity decreases, the ventilated supercavity is affected by both the free surface effect and the gravity effect.

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Section: Introductionmentioning

confidence: 58%

Numerical Investigation on the Ventilated Supercavity around a Body under Free Surface Effect

Zhi

Jin

Huang

et al. 2023

JMSE

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“…The values of Re and We are determined by the viscosity and surface tension coefficients of the drag reducer solution. According to the experimental investigations of Jiang et al and Li et al, we know that the 200 ppm of CTAC (cetyltrimethylammonium chloride) solution has a zero shear viscosity of 0.005 Pa·s, a relaxation time of 0.08 s, and a surface tension coefficient of 0.0322 N/m. For a CTAC solution of 500 ppm, its zero shear viscosity is 0.008 Pa·s, relaxation time is 0.2 s, and surface tension coefficient is 0.0336 N/m.…”

Section: Simulation Modelsmentioning

confidence: 99%

Numerical Study on Cavitation Generation in a Water Jet Added with Turbulent Drag-Reducing Additives Based on Improved Cavitation Model and Cross Model

Deng

Guan

et al. 2018

Ind. Eng. Chem. Res.

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An improved cavitation model was proposed to simulate the cavitation phenomenon in a water jet added with turbulent drag-reducing additives. The Cross model which expressed the shear-thinning properties of drag-reducer solution was also employed. The neglected viscous term and surface tension term in traditional cavitation models were reconsidered as viscosity, and surface tension force were important factors affecting bubbles' motion in drag-reducer solution. The numerical solutions of bubble radius in dragreducer solutions of different concentrations were fitted, and the change rates were added to the original mass transfer mechanism equations. The results showed that the modified cavitation model described the cavitation characteristics in drag-reducer solutions more accurately and effectively reflected that the cavitation region's wake became longer with the increase concentration of the drag reducing agent. When the concentration increased, the distribution of cavitation cloud became more homogeneous, and the pressure curve and velocity curve both changed more smoothly.

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“…In Li's study, he recorded the trajectories of bullets projected into cetyltrimethyl ammonium chloride aqueous solution of different mass fraction by using highspeed CCD camera, and finally observed the supercavities configuration around bullets. Jiang [28,29,34] also conducted experimental and numerical study on the effects of drag-reducing additives on supercavities. In his investigation, he used cross-viscosity model to calculate the dynamic viscosity of the drag-reducing solution and then simulated the supercavities' behavior.…”

Section: Insteadmentioning

confidence: 99%

“…The traditional way of dealing with the viscosity factor is to introduce the changing dynamic viscosity and turbulent viscosity into the momentum conversation equation and k-ε equation. For example, the numerical simulation by Panov et al [27] of steady cavitating of viscous fluid in a Francis hydroturbine and the numerical study on the behavior of water-entry supercavitating flow around a cylindrical projectile influenced by turbulent drag-reducing additives by Jiang [28,29].…”

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confidence: 99%

Numerical investigation on the orifice cavitating water jet considering the fluid viscosity’s effects on bubbles’ growth and collapse

Deng

Guan

2017

J Braz. Soc. Mech. Sci. Eng.

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The initial radius of bubble t Time ρ m The density of mixture u m The velocity of mixture μ m The viscosity of mixture α The volume fraction of vapor phase ρ v The density of vapor phase u v The velocity of vapor phase R e Mass transfer source term connected to the growth of the vapor bubbles R c Mass transfer source term connected to the collapse of the vapor bubbles n Bubble number density F vap Evaporation coefficient F cond Condensation coefficient ℜ B Bubble radius 1 Introduction Cavitation is a common hydraulic phenomenon in nature, and the collapse of the bubbles will generate a significant force of impact. So, cavitating water jets are widely used in many engineering fields such as cleaning, cutting, mining and improving the fatigue strength of materials [1-5]. Many experiments and simulations have been conducted to investigate cavitating water jets [6-11]. Since the computational fluid dynamics (CFD) was put forward in 1950s, Abstract This paper attempts to investigate the effects of fluid viscosity on cavitation generation. Different from the traditional cavitation models in which the Rayleigh-Plesset equation is simplified neglecting the second-order term and the surface tension force term, the primitive R-P equations with different dynamic viscosity values are solved by mathematical software and numerical solutions are obtained. Then, the method of curve fitting is selected to get the approximate expressions of bubble radius about time. Based on the expressions, the rate of change of bubble radius about time under different viscous conditions can be approximately obtained which will be written as in-house code to enhance the traditional cavitation models by UDFs. Numerical simulations of high-speed water jets issuing from a nozzle are carried out. The simulated cavitation characteristics match the supercavity experiments very well. The result shows a more homogenous distribution of vapor volume fraction while the viscosity of fluid increases. The pressure and velocity also change more slowly and smoothly along the nozzle under more viscous conditions. Simulations of external flow fields are also made based on the modified model to show the cavitation characteristics under submerged condition.

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Numerical study on evolution of axisymmetric natural supercavitation influenced by turbulent drag-reducing additives

Cited by 17 publications

References 14 publications

Numerical Investigation on the Ventilated Supercavity around a Body under Free Surface Effect

Numerical Investigation on the Ventilated Supercavity around a Body under Free Surface Effect

Numerical Study on Cavitation Generation in a Water Jet Added with Turbulent Drag-Reducing Additives Based on Improved Cavitation Model and Cross Model

Numerical investigation on the orifice cavitating water jet considering the fluid viscosity’s effects on bubbles’ growth and collapse

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