Journal of Shanghai Jiao Tong University ›› 2021, Vol. 55 ›› Issue (2): 161-169.doi: 10.16183/j.cnki.jsjtu.2020.066

Special Issue: 《上海交通大学学报》2021年12期专题汇总专辑 《上海交通大学学报》2021年“工程力学”专题

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Numerical Studies on Violent Sloshing and Resonance Frequencies in a Three-Dimensional Prismatic Tank

XIN Jianjian1(), FANG Tian2, SHI Fulong3   

  1. 1.Faculty of Maritime and Transportation, Ningbo University, Ningbo 315211, Zhejiang, China
    2.China Ship Scientific Research Center, Wuxi 214082, Jiangsu, China
    3.School of Transportation, Wuhan University of Technology, Wuhan 430063, China
  • Received:2020-03-10 Online:2021-02-01 Published:2021-03-03

Abstract:

To predict the resonance frequency of the real liquefied natural gas (LNG) tank, a Cartesian grid based three-dimensional (3D) multiphase flow model is used to simulate violent sloshing in a prismatic tank at different filling levels and excitation frequencies. In this model, a semi-implicit finite difference method is adopted to solve the incompressible two-phase flow Navier-Stokes (N-S) equations on a staggered Cartesian grid. Besides, a radial basis function ghost cell method (RBFGCM) is used to treat the irregular tank walls and a 3D gradient-augmented level set (GALS) method is used to capture highly nonlinear free surfaces. Based on the present model, the violent sloshing induced by rolling excitations in the 3D prismatic tank is simulated. Satisfactory convergences of grid sizes and time steps demonstrate the high accuracy and reliability of the present method. Moreover, the present results of the impulsive pressure and wave elevation agree well with the experimental data for different filling water depths. In addition, violent sloshing phenomena are captured such as wave rolling. Furthermore, the relationship between the pressure amplitude on the tank wall and the excitation frequency at four filling levels are investigated to identify the resonance frequency of the prismatic tank, to provide theorical guides for structrual design of the tanks.

Key words: Cartesian grid, level set method, sloshing, prismatic tank, resonance frequency

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