Study of Characteristics of Cloud Cavity Around Axisymmetric Projectile by Large Eddy Simulation

Abstract

Cavitation generally occurs where the pressure is lower than the saturated vapor pressure. Based on large eddy simulation (LES) methodology, an approach is developed to simulate dynamic behaviors of cavitation, using k À l transport equation for subgrid terms combined with volume of fluid (VOF) description of cavitation and the Kunz model for mass transfer. The computation model is applied in a 3D field with an axisymmetric projectile at cavitation number r ¼ 0.58. Evolution of cavitation in simulation is consistent with the experiment. Clear understanding about cavitation can be obtained from the simulation in which many details and mechanisms are present. The phenomenon of boundary separation and re-entry jet are observed. Re-entry jet plays an important role in the bubble shedding.

Experimental and numerical investigation on cloud cavitating flow around an axisymmetric projectile near the wall with emphasis on the analysis of local cavity shedding

“…Turbulent flow is simulated by a LES method (Yu et al, 2014;Wang et al, 2016aWang et al, , 2016bWu et al, 2016). In the LES method, large-scale eddies are simulated by solving instantaneous Navier-Stokes equations directly, while small-scale eddies are reflected by the sub-grid scale (SGS) model (Nicoud and Ducros, 1999).…”

“…Yu et al Ocean Engineering 140 (2017) 377-387 phase transfer rates are denoted by C v and C c . The empirical constants are set as: C = 200 v and C = 100 c , which are chosen from vast computational experience (Wang et al, , 2015a(Wang et al, , 2015bYu et al, 2014Yu et al, , 2017.…”

“…As proposed by Yu et al (2014) and Wu et al (2016), the numerical simulation is realized using the OpenFOAM framework with the firstorder Euler implicit scheme for time discretization and Gauss linear scheme for spatial discretization. An adjustable time step is used with maximum Courant number (Co) of 0.3 to reach a high-accuracy in time.…”

“…Detailed C. Yu et al Ocean Engineering 140 (2017) 377-387 experimental results and analysis can be found in previous literature (Yu et al, 2014). When the projectile is launched near the wall, the cavitation around the axisymmetric projectile has many non-axisymmetric characteristics and is more unstable.…”

“…Lu et al (2014) simulated the cavitating flow around two highly skewed propellers operating in open water and mounted on an inclined shaft using and approach based on LES methods. Yu et al (2014) simulated the cavitating flow around an axisymmetric projectile with cavitation number σ = 0.58 using LES methods. Their numerical results were in good agreement with the experiment, and presented various cavitation details and mechanisms.…”