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Zhou Y.,Shanghai JiaoTong University | Zhou Y.,Shanghai Rules and Research Institute | Ma N.,Shanghai JiaoTong University | Gu J.,Shanghai JiaoTong University
Ship Building of China | Year: 2013

Parametric rolling in head seas as one of the main stability failure models has attracted significant attentions of the International Maritime Organization (IMO). Roll moment of inertia is one of the key factors for predicting parametric rolling, since it has strong effect on natural roll period. In this paper, total of four calculation methods of roll moment of inertia are compared with each other and a 3 DOF weakly non-linear model is presented to study their effects on the prediction of parametric rolling. Radiation force and diffraction force are calculated based on 3D frequency-domain method, and time-delay effect is taken into account with the help of impulse response theory. The effect of different calculation methods of roll moment of inertia on the response of motion is discussed based on the vulnerability analysis of 3 actual container ships, and a simplified empirical approach of roll moment of inertia is given, which could be applied to the second generation intact stability criteria for parametric rolling prediction. Source

Chen G.-Q.,Hefei University of Technology | Zhuang L.,Hefei University of Technology | Zhuang L.,Shanghai Rules and Research Institute | Zhou J.-B.,Hefei University of Technology | And 2 more authors.
Ranshao Kexue Yu Jishu/Journal of Combustion Science and Technology | Year: 2011

Oscillation form, spreading velocity, oscillation frequency and amplitude of aviation fuel flame spreading were analyzed. When fuel temperature increased within the critical value, the spreading velocity and oscillation frequency of main flame and the oscillation amplitude of flash flame increased. Semi-empirical models were also developed to predict flame spreading velocity and oscillation frequency under different fuel temperature. Source

Zhang W.,South China University of Technology | Tang Y.,South China University of Technology | Zhao C.,South China University of Technology | Zhang C.,South China University of Technology | Zhang C.,Shanghai Rules and Research Institute
Applied Mechanics and Materials | Year: 2012

A numerical model based on the two-phase flow model for incompressible viscous fluid with a complex free surface has been developed in this study. The two-step projection method is employed to solve the Navier-Stokes equations in the numerical solutions, and finite difference method on a staggered grid is used throughout the computation. The two-order accurate volume of fluid (VOF) method is used to track the distorted and broken free surfaces. The two-phase model is first validated by simulating the dam break over a dry bed, in which the numerical results and experimental data agree well. Then 2-D fluid sloshing in a horizontally excited rectangular tank at different excitation frequencies is simulated using this two-phase model. The results of this study show that the two-phase flow model with VOF method is a potential tool for the simulation of nonlinear fluid sloshing. These studies demonstrate the capability of the two-phase model to simulate free surface flow problems with considering air movement effects. © (2012) Trans Tech Publications, Switzerland. Source

Ding S.-F.,Shanghai JiaoTong University | Ding S.-F.,Shanghai Rules and Research Institute | Tang W.-Y.,Shanghai JiaoTong University | Zhang S.-K.,Shanghai JiaoTong University
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2010

In considering that the change of material performance in relation to temperature has an important impact on the research of the structural safety of an LNG carrier, it was concluded that the elastic modules, poisson ratio, and thermal expansion coefficient of the materials appear to have a nonlinear change in relation to temperature. MARC was taken as a calculation tool, a typical hollow cavity model of an LNG carrier was selected, and contrast analysis for a partial temperature field and temperature stress was conducted. These steps were taken to investigate the sensitivity of the partial strength of an LNG carrier against nonlinearity of material. The result shows that a difference exists for whether or not nonlinearity of material is considered-in the former case, the thermal stress value is small, and in general, it is a conservative way not to consider the nonlinear factor of material. Source

Zhang C.,Shanghai Rules and Research Institute | Zhang C.,South China University of Technology | Lin N.,South China University of Technology | Tang Y.,Center for Maritime Engineering | Zhao C.,South China University of Technology
Computers and Fluids | Year: 2014

In this study, a finite difference model for the viscous incompressible Navier-Stokes (N-S) equations is developed to investigate problems with respect to wave-structure interaction. A two-step projection algorithm is employed to discretize the N-S equations on a fixed Cartesian grid. Coupled with wave generating and absorbing options, the model captures free surfaces using a volume-of-fluid method with a second-order piecewise linear interface construction (PLIC-VOF). In addition, a second-order sharp interface immersed boundary (SI-IB) method is utilized to account for the no-slip boundary condition on structure surfaces. The new model is capable of simulating free surface flows and their interaction with a stationary or moving structure, and wave generating and absorbing options are available in the model for some specific cases. To validate the model from different aspects, a series of numerical experiments are conducted. These tests include an oscillating cylinder in fluid without a free surface, liquid sloshing in a tank, water exit and entry of a horizontal cylinder, some wave generation and absorption tests, and a solitary wave over a submerged rectangular obstacle. Excellent agreement is obtained when the results are compared to analytical, experimental and other numerical results. Furthermore, two cases of a submerged and a semi-submerged ellipse rotating in a tank are investigated, and some significant phenomena are observed. © 2013 Elsevier Ltd. Source

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