Mechanical Engineering

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In the present study a novel modeling approach is presented to solve the combined internal sloshing and sea-keeping problem. The model deals with interesting effects arising due to the coupled interaction between the sloshing in partially filled containers of several geometries and the ship motion. The study is very important for the liquid cargo carrier operating in rough sea or under different environmental conditions. The resulting slosh characteristics that include transient pressure variation, free surface profiles and hydrodynamic pressure over the container walls have been reported in this study. In addition, the effects of coupled ship response and sloshing on ship motion parameters have also been investigated. The equations of motion of fluid, considered inviscid, irrota-tional, and partially compressible, are expressed in terms of the pressure variable alone. A finite difference-based iterative time-stepping technique is employed to advance the coupled solution in the time domain. Several parameters of interest, including the container parameters, level of liquid, thrusters modeling and some important environmental factors are investigated. © 2012 JASNAOE.

(SoE) School of Engineering

World University root node

Journal of Marine Science and Technology (Japan)

A fully coupled ship motion and sloshing analysis in various container geometries

The dynamic behavior of liquids in moving containers is a fascinating subject that has attracted the attention of geophysicists, seismologists, engineers, mathematicians and other scientific workers for many years. One of the design issues of the liquid-tank system is the sloshing phenomenon where internal fluid may result in severe damage to the containment system. The slosh dynamics of liquid storage tanks can be strongly influenced by the presence of internal submerged components. The internal components can modify the dynamic characteristics of the liquid tank systems to an advantage. The use of baffles as anti-slosh device is a quite well known example. The baffles cause a variation in the fundamental frequency of liquid oscillations by effectively changing the tank geometry. This paper describes the numerical assessment of lateral sloshing forces developed within liquid filled tanks with various internal components. The main contribution in this paper is that how the slosh dynamics of liquid filled container gets affected due to presence of multiple submerged block and baffle over a partition wall which is still dearth in open literature. © 2010 Begell House, Inc.

International Journal of Fluid Mechanics Research

Influence of various internal components on slosh dynamics: A study using finite element method

Math-based models developed by the MSU/CAVS team have considered both the compaction and sintering processes. Due to the very large number of input variables for the compaction model it is helpful to understand how sensitive the model output is to small changes in these input variables in order to better apply the model to real world processes. Using numerical methods both uncertainty and sensitivity analysis can be applied to the model and the most significant terms identified. Through further numerical analysis the output of the compaction model can be optimized for one or more output parameters, e.g. least density variation, lowest mass, minimal part thickness. These techniques will be illustrated using a well-established automotive PM product, the main bearing cap.

Advances in Powder Metallurgy and Particulate Materials - 2009, Proceedings of the 2009 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2009

Process modeling: Use of uncertainty, sensitivity and optimization techniques for improved understanding of compaction model outputs

Sloshing is a potential source of disturbance in liquid storage containers. Coupling effects of ship motion with fluid oscillation inside three- dimensional rectangular containers using a newly developed time domain simulation scheme were studied. Some representative studies are carried out by the authors. When the free-surface profile is involved, the three-dimensional effects became more significant. Coupled analysis predicted that the effect on the ship motion can be even up to 30% due to sloshing inside the container. The results advance the understanding of the dynamic behavior of LNG carrier in three dimensions interacting with the external hydrodynamics. This is an abstract of a paper from Proceedings of the Nineteenth (2009) International Offshore and Polar Engineering Conference (Osaka, Japan 6/21-26/2009).

Proceedings of the International Offshore and Polar Engineering Conference

A study on complicated coupling effects of 3-D sloshing in rectangular tanks and ship motion

Sloshing is a potential source of disturbance in liquid storage containers. Sloshing flow in ship cargo is excited by ship motion, but the sloshing flow itself affects the ship motion in return. This paper investigates the coupling effects of ship motion with fluid oscillation inside three dimensional rectangular containers using a newly developed time domain simulation scheme. The method has been applied to a number of problems and some typical results are presented that assess the accuracy and applicability of the method. Copyright © 2009 by The International Society of Offshore and Polar Engineers (ISOPE).

This paper deals with pressure-based finite element analysis of fluid-structure systems considering the coupled fluid and structural dynamics. The present method uses two-dimensional fluid elements and structural line elements for the numerical simulation of the problem. The equations of motion of the fluid, considered inviscid and compressible, are expressed in terms of the pressure variable alone. The solution of the coupled system is accomplished by solving the two systems separately with the interaction effects at the fluid-solid interface enforced by an iterative scheme. Non-divergent pressure and displacement are obtained simultaneously through iterations. The Galerkin weighted residual method-based FE formulation and the iterative solution procedure are explained in detail followed by some numerical examples. Numerical results are compared with the existing solutions to validate the code for sloshing with fluid-structure coupling. © 2008 Elsevier B.V. All rights reserved.

Finite Elements in Analysis and Design

2D simulation of fluid-structure interaction using finite element method

This paper brings into focus some of the interesting effects arising from the motion of the liquid free surface due to sloshing in partially filled containers of several geometrical shapes in two dimensions. The slosh characteristics that include frequencies, free surface profiles and the hydrodynamic pressure over the container walls have been reported in this study. The equations of motion of the fluid, considered inviscid, are expressed in terms of the pressure variable alone. It is assumed that the frequency of the exciting oscillation is not in the immediate neighborhood of the natural slosh frequency, so that the slope of the free surface is small. Simple harmonic oscillation and earthquake excitations are used as the prescribed boundary conditions. A finite difference-based iterative time-stepping technique is employed to advance the solution in the time domain. The paper presents numerical solutions for rectangular, vertically mounted annular cylindrical, trapezoidal and horizontal circular cylindrical containers. Numerical results obtained are compared with the available existing solutions to validate the code developed. The parametric study of the slosh dynamic systems shows the importance of the nature of excitation, fluid height and the geometry of the container. Copyright © 2007 John Wiley & Sons, Ltd.

International Journal for Numerical Methods in Fluids

Slosh dynamics of inviscid fluids in two-dimensional tanks of various geometry using finite element method

Seismic response of liquid storage tank can be strongly influenced by the presence of submerged components. This modification of the dynamic characteristics of the liquid tank systems with internal components can be very useful for improving their seismic behavior. In this paper, a pressure-based finite element technique has been developed to analyze the slosh dynamics of a partially filled rigid container with bottom-mounted submerged components. The fluid is assumed homogeneous, isotropic, inviscid, and to exhibit only limited compressibility. The problem is linearized assuming the frequency of the exciting oscillation not in the immediate neighborhood of the natural slosh frequency, so that the slope of the free surface is small. The linearized problem is spatially discretized using the Galerkin weighted residual method. Earthquake excitations are used as the prescribed boundary condition. The solution is advanced in time using Newmark's constant average acceleration method. The developed code has been used to investigate the effect of a bottom-mounted rectangular component on the slosh dynamics of a liquid-filled rigid container. Numerical results obtained are compared with the existing solutions to validate the code. The parametric study of the tank-fluid system shows the importance of height, width and location of the submerged structural components. © 2007 Elsevier Ltd. All rights reserved.

Journal of Sound and Vibration

Slosh dynamics of liquid-filled containers with submerged components using pressure-based finite element method

The work presented herein can broadly be categorized as a fluid-structure interaction problem. The response of a circular cylindrical structure subjected to cross flow is examined using the finite element method for both the liquid and the structure domains. The cylindrical tube is mounted elastically at the ends and is free to move under the action of the unsteady flow-induced forces. The fluid is considered to be partially compressible and viscous. The flow field is solved using a finite element method applied to the time-dependent Navier-Stokes equations. The cylinder motion is modeled using a five-degrees of freedom generalized shell element structural dynamics model. The numerical simulations of the response of the calandria tubes/pressure tubes, adjuster rod and shut-off rod of a nuclear reactor are presented. A few typical results are presented to assess the accuracy of the developed modules. Copyright © 2005 by ASME.