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.

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

Experimental Tests for Suppression Effects of Water Restraint Plates on Sloshing of a Water Pool

1988 ◽  
Vol 110 (3) ◽  
pp. 240-246 ◽  
Author(s):  
K. Muto ◽  
Y. Kasai ◽  
M. Nakahara
Keyword(s):  
Forced Vibration ◽  
Experimental Tests ◽  
Spent Fuel ◽  
Water Pool ◽  
Nuclear Facilities ◽  
Fuel Storage ◽  
Type Water ◽  
Vibration Tests ◽  
Sloshing Suppression ◽  
Suppression Effects

Forced vibration tests for a spent fuel storage pool of nuclear facilities [1] were conducted for the purpose of determining sloshing suppression effects. The devices reported in this paper are cantilever-type water restraint plates. They reduce sloshing and also prevent overflow of water from the pool. Parameters examined in the experimental tests were the installation height levels, lengths and shapes of the water restraint plates. The most effective installation conditions of these water restraint plates were found through the tests.

Aeroelastic Stability of a Transport Aircraft With Wing Mounted Store Suspension: Part I — Analysis

Volume 2 ◽  
2004 ◽  
Author(s):  
Altan Kayran
Keyword(s):  
Ground Vibration ◽  
Free Vibration Analysis ◽  
Point Of View ◽  
Scale Model ◽  
Vibration Test ◽  
Aeroelastic Stability ◽  
Transport Aircraft ◽  
Ground Testing ◽  
Modes Of Vibration ◽  
Local Store

The present study outlines the analysis work, backed by the relevant ground testing, performed for the verification of aeroelastic stability of a transport aircraft modified with the installation of an external store to the outer wing. The initial analysis work consisted of free vibration analysis and ground vibration testing of the modified aircraft for the identification of the natural frequencies and associated modes of vibration in still air. The beam-like half scale model of the aircraft was updated based on the results of the ground vibration test. External store wing connection stiffness was determined by means of vibration test performed for the identification of local store-wing structural interface modes. The dynamic model was updated again and flutter analyses were performed for different mass configurations of the aircraft. Mass configurations that are critical from flutter point of view were identified. Analysis results indicate that the flutter speeds of the aircraft with wing mounted store suspension, although lowered compared to the basic aircraft, stay above the values required by the flutter regulation MIL-A-8870C.

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.

Behavior of Full-Scale Model Cask Under 9m Drop Test and Simulation

2006 ◽  
Author(s):  
Kiminobu Hojo ◽  
Tadashi Kimura ◽  
Akio Kitada ◽  
Hiroshi Tamaki ◽  
Junich Kishimoto ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Dynamic Response ◽  
Nuclear Power ◽  
Simulation Method ◽  
Full Scale ◽  
Drop Test ◽  
Scale Model ◽  
Test Facility ◽  
Spent Fuel ◽  
Federal Institute

The nuclear spent fuel transport and storage cask is used for transport of the spent fuel from a nuclear power station to an intermediate storage facility. Leak tightness and subcriticality on transportation required from IAEA TS-R1 [1] have to be assured by a 9m drop test and its numerical simulation. This paper describes the drop test using a full-scale prototype test cask. The test was conducted by German Federal Institute for Materials Research and Testing (BAM) at their test facility in Horstwalde, Germany and comparison of the test result with the “MH1 (Mitsubishi Heavy Industries, Ltd.)” numerical simulation using LS-DYNA code. The drop orientations of the tests were slap down and vertical. From the drop test the following is demonstrated: • The leak rate of He gas after the drop tests satisfied the IAEA’s criteria. • The numerical simulation which modeled the cask body enabled dynamic response such as acceleration and strain of the cask body. This means the simulation method qualified the relation of dynamic response of the cask body and leakage behavior.

Analytical and Numerical Evaluation of the Impact Limiters Design of a Research Reactors Spent Fuel Transportation Package Half Scale Model Under 9 M Drop Tests

2008 ◽  
Author(s):  
Miguel Mattar Neto ◽  
Carlos A. J. Miranda ◽  
Gerson Fainer ◽  
Roge´rio P. Moura˜o
Keyword(s):  
Scale Model ◽  
Spent Fuel ◽  
Energy Agency ◽  
Dual Purpose ◽  
Research Reactors ◽  
Agency Support ◽  
Drop Tests ◽  
Accident Conditions ◽  
Regional Projects ◽  
The Impact

Since 2001, under the IAEA (International Atomic Energy Agency) support, some regional projects have been developed in Latin America to assess storage and transportion options for the research reactors spent fuel in the region. One of the projects tasks is the design and testing of a half scale model of a dual purpose (transportation and storage) package for research reactors spent fuel. Considering one of the hypothetical accident conditions, the 9 m drop test, this paper presents the impact limiters design evaluation of the above mentioned half scale model of the dual purpose package based on the impact limiters materials characterization, on the analytical assessment of the impact limiters sizing (dimensions and expected package acceleration levels) and on numerical simulations of the drop tests using a finite element explicit code. Conclusions and comments are addressed based on the obtained results.

Study of Correlation Between Beam Vibration and Oval Vibration on Cylindrical Water Storage Tank

2005 ◽  
Author(s):  
Akira Maekawa ◽  
Yasutaka Shimizu ◽  
Michiaki Suzuki ◽  
Katsuhisa Fujita
Keyword(s):  
Natural Frequency ◽  
Large Amplitude ◽  
Storage Tank ◽  
Excitation Frequency ◽  
Water Storage ◽  
Scale Model ◽  
Vibration Test ◽  
Large Radius ◽  
Water Storage Tank ◽  
Test Tank

A large cylindrical water storage tank, widely used at power stations and chemical plants, typically has a large radius/wall-thickness ratio. The relatively thin sidewall of such a tank can deform easily during an earthquake due to vibrations of the tank structure. In order to improve the seismic-proof design practices for a water storage tank of flexible structure and to develop a new seismic resistance evaluation method to be adopted in future, it is important to understand the dynamic responses of such a tank to seismic motions including the nonlinearity of responses to large amplitude vibrations. This paper reports on the results of vibration test, in which sinusoidal wave excitations with large amplitude were conduced to the scale model tank of a thin-walled cylindrical water storage tank, and the theoretical analysis of the dynamics of the vibratory behaviors that were observed during the vibration test. First, a frequency sweep test was performed over the range that covered the natural frequency. The response of the test tank as a whole to given vibrations remained almost the same over the excitation frequency range. Frequency analysis of the response of the tank failed to locate any resonance points at or around frequencies that had been determined by the basic vibration characteristic test that we had conducted in advance. Next, a large amplitude excitation tests were carried out, in which the test tank was excited intensively by several tens of sinusoidal waves of a fixed frequency that was in the vicinity of the resonant frequency. The response of the tank as a whole in the form of beam vibrations did not intensify in proportion to the input acceleration; it did not go beyond a certain level. Since both of the tests produced significant oval vibrations on the sidewall of tank, the influence of oval vibrations over beam vibrations was analyzed. The analysis concerning the deflection of the sidewall of tank by the additional appearance of oval vibrations in the presence of beam vibrations revealed that a major decrease in the flexural rigidity reduced the response (beam vibrations) of the whole tank. The phenomenon was modeled using a nonlinear equation of motion, assumed that the rigidity depended on the amplitude of oval vibrations. The analysis using this equation explained the results of the above-mentioned tests very well. Thus, it was demonstrated both empirically and analytically that beam vibrations of a cylindrical water storage tank are reduced by the appearance of oval vibrations that have the effect of lowering the natural frequency.

Construction of Dynamic Model for Free Standing Spent Fuel Rack Under Seismic Excitations

2015 ◽  
Author(s):  
Shigehiko Kaneko ◽  
Hironao Shirai
Keyword(s):  
Dynamic Model ◽  
Nuclear Power ◽  
Scale Model ◽  
Spent Fuel ◽  
Seismic Excitations ◽  
Power Station ◽  
Free Standing ◽  
Method Of Calculation ◽  
Gap Flow ◽  
Real Size

Free standing rack designed for storing spent fuel at nuclear power station has an advantage to earthquake excitations because both fluid force and friction force can reduce the movement of a rack. However, there are various motions of FS rack such as parallel, rotational and rocking which should be taken into consideration when it is subjected to earthquake excitations. Therefore, the motion of FS rack must be precisely figured out in order to apply FS rack design concept. In this research, to investigate the motion of FS rack, 2-dimensional dynamic model considering pressure loss of gap flow was constructed. In addition, an experiment with a 1/16 scale model was conducted to validate the dynamic model. From numerical results based on the proposed dynamic model, some important features for the design of FS rack were found. Finally, case studies by real size free standing rack under the excitation of actually observed earthquake wave like The Great East Japan earthquake and The Niigata-ken Chuetsu-Oki earthquake were conducted based on the proposed method of calculation.

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