scholarly journals Modeling of Liquid Hot Metal Sloshing in Ladles During Transportation by Locomotives (A Bond Graph Method)

2019 ◽  
Vol 8 (2S10) ◽  
pp. 548-551
Keyword(s):  
Free Surface ◽  
Hydrodynamic Pressure ◽  
Bond Graph ◽  
Common Phenomenon ◽  
Hot Metal ◽  
External Excitation ◽  
Sloshing Dynamics ◽  
Open Container ◽  
External Forces ◽  
Inside Wall

Safe and secure transportation of liquid hot metal in steel plants is very challenging. About ninety percent of transportation is by means of locomotives. Sloshing is a common phenomenon in open container liquid transportation due to external excitation. Non-linear sloshing dynamics of liquid hot metal in ladle due to locomotive movement is the prime consideration of this paper. Liquid hot metal inside the ladle has been considered in the line of an equivalent mechanical system. Resulting forces and moments acting on the ladle inside wall are considered equal in all senses. An equivalent mechanical dynamic system representation of sloshing by bond graph modellinghas been formulated by keeping records in a satisfactory way.Future research scopes has been identifiedin parallel with an outline mapped. Hot metal liquid has two distinct components of the hydrodynamic pressure in consideration of rigid containershas been identified. Bottom segment of the molten metal column moves unison with the ladleandis directlyproportional with the acceleration of the ladle. Whereas the second one ‘convective’ pressure at the free surface, particularly experiences the sloshing tendency due to external forces.

scholarly journals Experimental and Numerical Studies on Sloshing Dynamics of PCS Water Tank of Nuclear Island Building

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaojun Li ◽  
Chenning Song ◽  
Guoliang Zhou ◽  
Chao Wei ◽  
Ming Lu
Keyword(s):  
Shaking Table Test ◽  
Cooling System ◽  
Damping Ratio ◽  
Time History ◽  
Hydrodynamic Pressure ◽  
Test Method ◽  
Shaking Table ◽  
Water Tank ◽  
Scaled Model ◽  
Sloshing Dynamics

Water tank is one important component of passive containment cooling system (PCS) of nuclear island building. The sloshing frequency of water is much less than structure frequency and large-amplitude sloshing occurs easily when subjected to seismic loadings. Therefore, the sloshing dynamics and fluid-structure interaction (FSI) effect of water tank should be considered when the dynamic response of nuclear island building is analyzed. A 1/16 scaled model was designed and the shaking table test was done, in which the hydrodynamic pressure time histories and attenuation data of wave height were recorded. Then the sloshing frequencies and 1st sloshing damping ratio were recognized. Moreover, modal analysis and time history analysis of numerical model were done by ADINA software. By comparing the sloshing frequencies and hydrodynamic pressures, it is proved that the test method is reasonable and the formulation of potential-based fluid elements (PBFE) can be used to simulate FSI effect of nuclear island building.

scholarly journals Finite Element Simulation of Dynamic Stability of Plane Free-Surface of a Liquid under Vertical Excitation

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Siva Srinivas Kolukula ◽  
P. Chellapandi
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Parametric Resonance ◽  
Linear Equations ◽  
Parametric Instability ◽  
Initial Perturbation ◽  
Mathieu Equation ◽  
External Excitation ◽  
Nonlinear Potential Theory ◽  
Vertical Excitation

When partially filled liquid containers are excited vertically, the plane free-surface of the liquid can be stable or unstable depending on the amplitude and frequency of the external excitation. For some combinations of amplitude and frequency, the free-surface undergoes unbounded motion leading to instability called parametric instability or parametric resonance, and, for few other combinations, the free-surface undergoes bounded stable motion. In parametric resonance, a small initial perturbation on the free-surface can build up unboundedly even for small external excitation, if the excitation acts on the tank for sufficiently long time. In this paper, the stability of the plane free-surface is investigated by numerical simulation. Stability chart for the governing Mathieu equation is plotted analytically using linear equations. Applying fully nonlinear finite element method based on nonlinear potential theory, the response of the plane free-surface is simulated for various cases.

Lagrangian Expressions of the Hydrodynamic Forces Acting on a Rigid Body in the Presence of a Free Surface

1985 ◽  
Vol 29 (01) ◽  
pp. 12-22
Author(s):  
G. A. Athanassoulis ◽  
T. A. Loukakis
Keyword(s):  
Free Surface ◽  
Rigid Body ◽  
Hydrodynamic Pressure ◽  
Hydrodynamic Forces ◽  
Ship Motions ◽  
Analytical Dynamics ◽  
Motion Equations ◽  
Hydromechanical System ◽  
Complete Set ◽  
Virtual Velocity

The formalism of classical analytical dynamics is used in conjunction with the principle of virtual velocity to derive Lagrangian expressions for the hydrodynamic forces acting on a rigid body moving through an in-viscid and incompressible liquid with a free surface. Simultaneously, a corresponding Lagrangian expression is derived for the hydrodynamic pressure acting on the free surface itself. The expressions for the hydrodynamic forces degenerate to the classical ones if the free surface is not present, and the expression for the pressure is reduced to that obtained by Milder if the rigid boundaries are all kept fixed. The derived Lagrangian expressions for the hydrodynamic reactions are used to obtain a complete set of motion equations for the examined hydromechanical system, and to discuss another Lagrangian approach to the ship-motions problem, presented by Wang.

Modeling Three-dimensional Free Surface Flow around Thin Wall Incorporation Hydrodynamic Pressure on δ-coordinate

2014 ◽  
Vol 16 (3) ◽  
pp. 327-336
Author(s):  
Hyo-Seob Kim ◽  
Ho-Jun Yoo ◽  
Jae-Yul Jin ◽  
Chang-Hwan Jang ◽  
Jung-Su Lee ◽  
...  
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Hydrodynamic Pressure ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Thin Wall

The Effect of Punching Plates to Suppress the Sloshing in a Gas Liquid Separator

2013 ◽  
Author(s):  
Hayato Suzuki ◽  
Shigehiko Kaneko
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Wave Height ◽  
Horizontal Cylinder ◽  
Free Surface Elevation ◽  
External Excitation ◽  
Resonant Wave ◽  
End Caps ◽  
Gas Fields ◽  
Liquid Separator

Natural gas is relatively clean and its demand is increasing these days. In most of the case, gas fields are located at the bottom of the sea. Therefore, Floating Production, Storage and Offloading (FPSO) system is now attracting big attention. This paper is related to dynamical design of FPSO system, specially focused on the free surface elevation in the horizontal cylindrical and axisymmetric liquid vessel with end caps induced by the wave. In this study, the theory on the wave height and resonant frequency in a horizontal cylinder subjected to longitudinal external excitation is developed. Then, the theory capable of taking account of the effect of punching plates is described. Finally, experimental data of resonant wave height up to 3rd mode are shown in comparison with theoretically derived results.

Random Excitation of a Structure Interacting With Liquid Sloshing Dynamics

2002 ◽  
Author(s):  
Takashi Ikeda ◽  
Raouf A. Ibrahim
Keyword(s):  
Free Surface ◽  
Natural Frequency ◽  
Internal Resonance ◽  
Gaussian White Noise ◽  
Liquid Sloshing ◽  
Elastic Structure ◽  
Center Frequency ◽  
System Response ◽  
Liquid Free Surface ◽  
Sloshing Dynamics

The nonlinear random interaction of an elastic structure with liquid sloshing dynamics in a cylindrical tank is investigated in the neighborhood of 1:2 internal resonance. Such internal resonance takes place when the natural frequency of the elastic structure is close to twice the natural frequency of the antisymmetric sloshing mode (1,1). The excitation is generated from the response of a linear shaping filter subjected to a Gaussian white noise. The analytical model involves three sloshing modes; (1,1), (0,1) and (2,1). The system response statistics and stability boundaries are numerically estimated using Monte Carlo simulation. The influence of the excitation center frequency, its bandwidth, and the liquid level on the system responses is studied. It is found that there is an irregular energy exchange between the structure and the liquid free surface motion when the center frequency is close to the structure natural frequency. Depending on the excitation power spectral density, the liquid free surface experiences zero motion, uncertain motion (intermittency), partially developed motion, and fully developed random motion. The structure response probability density function is almost Gaussian, while the liquid elevation deviates from normality. The unstable region, where the liquid motion occurs, becomes wider as the excitation intensity increases or as the bandwidth decreases. As the liquid depth decreases, the region of nonlinear interaction shrinks which is associated with a shift of the peak of the structure mean square response toward the left side of the frequency axis.

Chaos in a Weakly Nonlinear Oscillator With Parametric and External Resonances

1991 ◽  
Vol 58 (1) ◽  
pp. 244-250 ◽  
Author(s):  
K. Yagasaki
Keyword(s):  
Invariant Torus ◽  
Chaotic Dynamics ◽  
Averaging Method ◽  
Double Resonance ◽  
External Excitation ◽  
Chaotic Motions ◽  
Single Degree Of Freedom ◽  
Weakly Nonlinear ◽  
Single Degree ◽  
External Forces

This paper describes a study of the chaotic dynamics of a weakly nonlinear single degree-of-freedom system subjected to combined parametric and external excitation. We consider a case of double resonance in which primary resonances, with respect to parametric and external forces, exist simultaneously. By using the averaging method and Melnikov’s technique, it is shown that chaos may occur in certain parameter regions. These chaotic motions result from the existence of orbits homoclinic to a normally hyperbolic invariant torus which corresponds to a hyperbolic periodic orbit in the averaged system. The mechanism and structure of chaos in this situation are also described. Furthermore, the existence of steady-state chaos is demonstrated by numerical simulation.

The Effect of Punching Plates to Suppress the Sloshing in a Gas Liquid Separator

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Shigehiko Kaneko ◽  
Hayato Suzuki
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Wave Height ◽  
Horizontal Cylinder ◽  
Free Surface Elevation ◽  
External Excitation ◽  
Resonant Wave ◽  
End Caps ◽  
Gas Fields ◽  
Liquid Separator

Natural gas is relatively clean and its demand is increasing these days. In most of the case, gas fields are located at the bottom of the sea. Therefore, floating production, storage and offloading (FPSO) system is now attracting big attention. This paper is related to dynamical design of FPSO system, specially focused on the free surface elevation in the horizontal cylindrical and axisymmetric liquid vessel with end caps induced by the wave. In this study, the theory on the wave height and resonant frequency in a horizontal cylinder subjected to longitudinal external excitation is developed. Then, the theory capable of taking account of the effect of punching plates is described. Finally, experimental data of resonant wave height up to 3rd mode are shown in comparison with theoretically derived results.

scholarly journals Numerical Analysis of Hydrodynamic Loads on Passing and Moored Ships in Shallow Water

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 558
Author(s):  
Ji-Yong Park ◽  
Bo Woo Nam ◽  
Yonghwan Kim
Keyword(s):  
Free Surface ◽  
Surface Effect ◽  
Hydrodynamic Pressure ◽  
Simulation Method ◽  
Separation Distance ◽  
Hydrodynamic Forces ◽  
Surface Boundary ◽  
Surface Boundary Conditions ◽  
Surface Models ◽  
Force Time

In this study, hydrodynamic interactions between passing and moored ships were studied by applying a time-domain numerical simulation method. The boundary value problem for a fluid domain was formulated based on a potential flow theory. A numerical method was developed based on a finite element method with an efficient re-mesh algorithm. Regarding the free-surface boundary conditions, both double-body and free-surface models were considered for examining the free-surface effect on the hydrodynamic forces due to the passing ship. First, numerical results were validated by comparison with the model test results of Kriebel et al. (2005), where generic Series 60 hulls were considered as the target model for the passing and moored ships. In addition, hydrodynamic pressure fields and force time-series were investigated to understand the passing ship problem. Second, a series of numerical simulations were performed to study the effects of the passing ship speed, separation distance, water depth, and relative vessel size, which were used to compare the peak values of hydrodynamic forces. The applicability and limitations of the double-body and free-surface models are discussed for predicting passing ship loads.

An efficient methodology for simulating roll dynamics of a tank vehicle coupled with transient fluid slosh

2016 ◽  
Vol 23 (19) ◽  
pp. 3216-3232 ◽  
Author(s):  
Amir Kolaei ◽  
Subhash Rakheja ◽  
Marc J Richard
Keyword(s):  
Free Surface ◽  
Coordinate System ◽  
Fluid Dynamic ◽  
Separation Of Variables ◽  
Hydrodynamic Pressure ◽  
Computational Effort ◽  
Surface Boundary ◽  
Potential Flows ◽  
Free Surface Boundary Condition ◽  
Cartesian Coordinate

An efficient methodology is proposed for simulation of roll dynamics of a tank vehicle system coupled with transient hydrodynamic forces due to fluid slosh. The transient fluid slosh in a horizontal cylindrical tank is analytically modeled considering simultaneous lateral, vertical and roll excitations assuming potential flows and a linearized free-surface boundary condition. For this purpose, the fluid domain in the Cartesian coordinate system is transformed to the bipolar coordinates, where the Laplace equation could be solved using separation of variables. The resulting hydrodynamic pressure, free-surface elevation and slosh force and roll moment are formulated in the tank-fixed coordinate system. The transient fluid slosh model is subsequently integrated to a dynamic roll plane model of a tank vehicle combination to investigate the effect of transient liquid slosh on the roll stability of the vehicle during steady-turning as well as path-change maneuvers. The analyses are performed for different fluid fill heights considering both variable and constant cargo load conditions. The results suggest that the roll stability of tank vehicles can be efficiently analyzed using the coupled linear slosh and multi-body vehicle models with significantly lower computational effort than the methods employing computational fluid dynamic fluid slosh models.

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