scholarly journals Liquid sloshing dynamics in a barge carrying container subjected to random wave excitation

2012 ◽  
Vol 9 (1) ◽  
pp. 43-65 ◽  
Author(s):  
Nasar Thuvanismail ◽  
Sannasiraj Sannasi ◽  
Sundar Vallam
Keyword(s):  
Excitation Frequency ◽  
Primary Resonance ◽  
Peak Frequency ◽  
Experimental Program ◽  
Random Wave ◽  
Wave Excitation ◽  
Excitation Peak ◽  
Sloshing Dynamics ◽  
Sloshing Mode ◽  
Marine Engineering

The sloshing phenomenon of liquid in a partially filled tank mounted rigidly on a barge exposed to random beam waves has been investigated through a well controlled experimental program. Four relative liquid depths, (liquid depth, hs/ length of tank, l) of 0.163, 0.325, 0.488 and 0.585 were considered for the tests. The sloshing oscillation was measured along the length of the tank at predefined locations. The effect of variation of the peak wave excitation frequency on the sloshing oscillation in the frequency domain is studied. The dominant energy is found to be concentrated around lowest nth sloshing mode frequency and, secondary peaks are observed at higher order sloshing frequencies. Odd modes contributions are dominating even modes irrespective of the excitation peak frequency. The sacrifice of second mode is observed while the excitation peak frequency is closer to its primary resonance. DOI: http://dx.doi.org/10.3329/jname.v9i1.7600 Journal of Naval Architecture and Marine Engineering 9(2012) 43-65

Liquid Sloshing Dynamics in a Container Subjected to Coupled Mode Excitation

2008 ◽  
Author(s):  
T. Nasar ◽  
S. A. Sannasiraj ◽  
V. Sundar
Keyword(s):  
Excitation Frequency ◽  
Qualitative Assessment ◽  
Floating Body ◽  
Nonlinear Behaviour ◽  
Wave Excitation ◽  
Coupled Mode ◽  
Sloshing Dynamics ◽  
Time Histories ◽  
Fill Level ◽  
The Individual

An experimental work has been carried out to study the phenomena of sloshing of liquid in a partially filled tank mounted on a barge exposed to regular beam waves. Liquid fill level with aspect ratio (hs/l, where hs is the static liquid depth and l is the tank length) of 0.325 is studied. The time histories of sloshing oscillation are measured along the length of container at predefined locations. The nonlinear behaviour of sloshing oscillation is observed for the regular wave excitation. The spectra of the sloshing oscillation and their qualitative assessment are reported. The individual sway and heave analytical model have been studied in order to substantiate the importance of coupled mode of excitation. Attempts are made to evaluate the harmonics present in the sloshing oscillation and compare with the results of earlier studies. In the present interaction study, it was found that the nonlinear response of the floating body also plays a role to induce violent sloshing oscillation. The effects of wave excitation frequency on the sloshing oscillation are reported.

Experimental Investigation of Sloshing Dynamics Coupled With Barge Responses

2009 ◽  
Author(s):  
T. Nasar ◽  
S. A. Sannasiraj ◽  
V. Sundar
Keyword(s):  
Experimental Investigation ◽  
Wave Height ◽  
Natural Frequencies ◽  
Excitation Frequency ◽  
Wave Excitation ◽  
The Third ◽  
Sloshing Frequency ◽  
Sloshing Dynamics ◽  
Liquid Depth ◽  
Cover Up

An experimental work has been carried out to study the phenomena of sloshing of liquid in a partially filled tank with aspect ratio (hs/l, where hs is the static liquid depth and l is the tank length) of 0.585. The sloshing tank was rigidly fixed in to a barge and was exposed to regular beam waves. The wave excitation frequencies (fw) ranging from 0.70Hz to 1.54Hz that cover up to the third mode natural sloshing frequency (f3) are considered. The incident wave height (Hi) is 0.10m. The effects of wave excitation frequency and wave height on the sloshing oscillation are studied. Attempts are made to evaluate the harmonics present in the sloshing oscillation and compare with the results of earlier studies. The barge responses such as sway, heave and roll are measured and it is found that the barge responses at their natural frequencies are insensitive to induce sloshing oscillation inside the tank.

Effect of Porous Baffle on Sloshing Dynamics in a Barge Mounted Container Subjected to Wave Excitation

2017 ◽  
Author(s):  
Nasar Thuvanismail ◽  
Akshay P. Shah ◽  
Deepak J. Surahonne ◽  
Sannasiraj S. Annamalaisamy
Keyword(s):  
Experimental Investigation ◽  
Aspect Ratio ◽  
Water Level ◽  
Excitation Frequency ◽  
Experimental Setup ◽  
Regular Wave ◽  
Wave Excitation ◽  
Regular Waves ◽  
Sloshing Dynamics

An experimental investigation was carried out to determine the effect of porous baffle walls on sloshing dynamics of a sloshing tank that is partially filled with liquid and rigidly mounted in a barge. The experimental setup is subjected to beam sea regular wave excitations and hence the barge experiences combined sway heave and roll excitations. An aspect ratio (hs/l, where hs is still water level and l is length of tank) of 0.488 is considered which corresponds to 75% fill condition with respect to tank height. Three porosities of 15%, 20%, and 25% are considered. The barge system was subjected to regular waves of frequency (fw) ranging from 0.45Hz to 1.54Hz. The effectiveness of porous baffles on the dissipation of sloshing energy is studied in comparison with without baffle condition. The effect of wave excitation frequency on the sloshing dynamics has also been analysed and the prominent results are here in reported.

Sloshing Suppression Method for a Rectangular Pool Using Immersed Blocks and Baffle Plates

2014 ◽  
Author(s):  
Urara Watanabe ◽  
Hiroshi Niwa ◽  
Akira Tsuyuki ◽  
Masahiko Warashina ◽  
Ryo Ito ◽  
...  
Keyword(s):  
Scale Model ◽  
Random Wave ◽  
Vibration Test ◽  
Baffle Plate ◽  
Wave Excitation ◽  
Spent Fuel ◽  
Overhang Length ◽  
Sloshing Mode ◽  
Suppression Method ◽  
Sloshing Suppression

There is a possibility that water in a spent fuel storage pool may overflow due to sloshing during long-period earthquakes. Therefore, this paper presents two sloshing suppression methods for a rectangular pool to reduce the volume of overflow water. Vibration tests were carried out to evaluate the volume of overflow water. The 1/20-scale model pool is used. First method is applying immersed blocks on the bottom of the rectangular pool. The volume of the water over the sidewall should be the maximum when the 1st sloshing mode is excited, and this behavior has significant influence on the volume of overflow water. The immersed blocks suppress the 1st sloshing mode, thereby reducing the over flow water. Vibration test were conducted by changing the following conditions: height of blocks, open area ratio, block position in the excitation direction, and number of opening sections. Changing of the natural frequencies and the amplification ratios are confirmed by the sinusoidal sweep test. In random wave excitation tests, the volume of overflow water from the pool with the best configuration blocks is lower than about 60% of that from the regular pool. Second method is applying horizontal baffle plates on the sidewall of rectangular pool. Horizontal baffle plate is a well-known sloshing suppression method. However, there is a little information about the relationship between installation condition of baffle plate and volume of overflow water Vibration test were conducted by changing the following conditions: installation height level, overhang length of baffle plate. In random wave excitation tests, the volume of overflow water from the pool with the best installation condition baffle plate is lower than 40% of that from the regular pool.

Modeling and Experimental Validations of a Piezoelectric Energy Harvester Under Combined Galloping and Base Excitations

2014 ◽  
Author(s):  
Amin Bibo ◽  
Abdessattar Abdelkefi ◽  
Mohammed F. Daqaq
Keyword(s):  
Bluff Body ◽  
Energy Harvester ◽  
Constitutive Relations ◽  
Excitation Frequency ◽  
Primary Resonance ◽  
Beam Theory ◽  
Excitation Amplitude ◽  
The Body ◽  
Base Excitation ◽  
Piezoelectric Energy

This paper develops an experimentally validated model of a piezoelectric energy harvester under combined aeroelastic-galloping and base excitations. To that end, an energy harvester consisting of a thin piezoelectric cantilever beam subjected to vibratory base excitation is considered. To permit galloping excitation, a bluff body is rigidly attached at the free end such that a net aerodynamic lift is generated as the incoming airflow separates on both sides of the body giving rise to limit cycle oscillations when the flow velocity exceeds a critical value. A nonlinear electromechanical distributed-parameter model of the harvester under the combined excitation is derived using the energy approach and by adopting the nonlinear Euler-Bernoulli beam theory, linear constitutive relations for the piezoelectric transduction, and the quasi-steady assumption for the aerodynamic loading. The partial differential equations of the system are discretized and a reduced-order-model is obtained. The mathematical model is validated by conducting a series of experiments with different loading conditions represented by wind speed, base excitation amplitude, and excitation frequency around the primary resonance.

scholarly journals On the Application of the Multiple Scales Method on Electrostatically Actuated Resonators

2019 ◽  
Vol 14 (4) ◽  
Author(s):  
Saad Ilyas ◽  
Feras K. Alfosail ◽  
Mohammad I. Younis
Keyword(s):  
Analytical Solution ◽  
Multiple Scales ◽  
Excitation Frequency ◽  
Primary Resonance ◽  
Equation Of Motion ◽  
Higher Order ◽  
Resonance Excitation ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Electrostatically Actuated

We investigate modeling the dynamics of an electrostatically actuated resonator using the perturbation method of multiple time scales (MTS). First, we discuss two approaches to treat the nonlinear parallel-plate electrostatic force in the equation of motion and their impact on the application of MTS: expanding the force in Taylor series and multiplying both sides of the equation with the denominator of the forcing term. Considering a spring–mass–damper system excited electrostatically near primary resonance, it is concluded that, with consistent truncation of higher-order terms, both techniques yield same modulation equations. Then, we consider the problem of an electrostatically actuated resonator under simultaneous superharmonic and primary resonance excitation and derive a comprehensive analytical solution using MTS. The results of the analytical solution are compared against the numerical results obtained by long-time integration of the equation of motion. It is demonstrated that along with the direct excitation components at the excitation frequency and twice of that, higher-order parametric terms should also be included. Finally, the contributions of primary and superharmonic resonance toward the overall response of the resonator are examined.

Combined Steady State and Transient Analysis of a Patrol Vessel as Affected by Varying Amounts of Damping and Periodic and Random Wave Excitation

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Jeffrey M. Falzarano ◽  
Srinivas Vishnubhotla ◽  
Sarah E. Juckett
Keyword(s):  
Dynamical System ◽  
Steady State ◽  
Critical Behavior ◽  
Large Amplitude ◽  
Transient Analysis ◽  
System Analysis ◽  
Random Wave ◽  
Rolling Motion ◽  
Wave Excitation ◽  
Random Forcing

In this paper various techniques of dynamical system analysis are used to analyze the effect of damping on large amplitude nonlinear ship-rolling motion of a patrol vessel. In particular steady state magnification curves, Poincare maps are for harmonic forcing and project phase planes are for random forcing. It has been found that varying amounts of damping substantially affect the vessel’s critical behavior. This is important since most stability regulations ignore damping and solely concentrate on the vessel’s righting ram curve. Moreover roll damping is difficult to predict accurately and small changes in damping may have a significant effect.

scholarly journals Tunable asymmetric spin wave excitation and propagation in a magnetic system with two rectangular blocks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dongpyo Seo ◽  
S. Hwang ◽  
Byungro Kim ◽  
Yeonhee Yang ◽  
Seungha Yoon ◽  
...  
Keyword(s):  
Light Scattering ◽  
Spin Wave ◽  
Magnetic System ◽  
Excitation Frequency ◽  
Magnetic Memory ◽  
Asymmetry Ratio ◽  
Wave Excitation ◽  
Scattering Spectrum ◽  
Spin Wave Excitation ◽  
Light Scattering Spectrum

AbstractAsymmetric spin wave excitation and propagation are key properties to develop spin-based electronics, such as magnetic memory, spin information and logic devices. To date, such nonreciprocal effects cannot be manipulated in a system because of the geometrical magnetic configuration, while large values of asymmetry ratio are achieved. In this study, we suggest a new magnetic system with two blocks, in which the asymmetric intensity ratio can be changed between 0.276 and 1.43 by adjusting the excitation frequency between 7.8 GHz and 9.4 GHz. Because the two blocks have different widths, they have their own spin wave excitation frequency ranges. Indeed, the spin wave intensities in the two blocks, detected by the Brillouin light scattering spectrum, were observed to be frequency-dependent, yielding tuneable asymmetry ratio. Thus, this study provides a new path to enhance the application of spin waves in spin-based electronics.

Effect of Peak Excitation Frequency on Seismic Fatigue Damage of Plant Pipelines

2020 ◽  
Author(s):  
Fumio Inada ◽  
Michiya Sakai ◽  
Ryo Morita ◽  
Ichiro Tamura
Keyword(s):  
Fatigue Damage ◽  
Mode Shape ◽  
Excitation Frequency ◽  
Peak Frequency ◽  
New Method ◽  
Vibration Velocity ◽  
Frequency Change ◽  
Concentrated Mass ◽  
Input Acceleration ◽  
Cumulative Fatigue Damage

Abstract In a previous report, a new method of calculating the approximate seismic cumulative fatigue damage of plant pipelines was developed, in which the sum of the cumulative absolute velocities (CAV) of the pipeline response per cycle was calculated, and the result was applied to the allowable vibration velocity described in the ASME Operation and Maintenance (O/M) code 2012. The new method provided a conservative value of cumulative fatigue damage. In this present study, a parameter showing the effect of a concentrated mass attached to the tip of a cantilever pipe was obtained as a function of the ratio of the concentrated mass to the mass of the cantilever pipe by eigenmode calculation using ABAQUS. In the previous report, the new method was based on the relative response of the pipeline, whereas in this present study, the application of the method was expanded to evaluations using the CAV of the excitation input for each cycle. We conducted the fast forward simulation of a real earthquake to determine the effect of the peak frequency change on cumulative fatigue damage, and we found that the response of cumulative fatigue damage at the peak frequency tends to decrease with increasing peak excitation frequency, which was consistent with the results obtained using the previously reported new method. Both the new method and the newly expended method are based on the ASME O/M code, and the results obtained by these methods suggest that the peak frequency tends to affect general pipelines. In the calculations, when the configuration of the pipeline is fixed and the mode shape does not change, the cumulative fatigue damage was found to decrease with increasing peak frequency of input acceleration. If the mode shape changes with the peak input acceleration frequency, then cumulative fatigue damage is affected. Moreover, if the participation factor has a larger value in a higher mode, the cumulative fatigue damage also has a larger value.

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