Behavior of Unanchored Fluid-Filled Tanks Subjected to Ground Excitation

1988 ◽  
Vol 55 (3) ◽  
pp. 654-659 ◽  
Author(s):  
S. Natsiavas ◽  
C. D. Babcock
Keyword(s):  
Experimental Data ◽  
Dramatic Reduction ◽  
Base Excitation ◽  
Storage Tanks ◽  
Response Frequency ◽  
Qualitative And Quantitative ◽  
Liquid Storage ◽  
Beam Type ◽  
Effective Beam ◽  
Good Agreement

An analysis developed for the response of liquid storage tanks under horizontal base excitation is employed and numerical results are obtained for unanchored tanks. These results are compared and found to be in good agreement with experimental data. Base uplift is shown to cause a dramatic reduction in the effective beam-type stiffness of a tank, which in turn reduces the tank response frequency and changes the developed hydrodynamic loads significantly. Based on these results, an explanation is provided for some great qualitative and quantitative differences in the behavior of a tank, resulting from its base fixity condition alone.

Numerical Simulation of the Charging of Liquid Storage Tanks: Comparison With Experiment

1989 ◽  
Vol 111 (3) ◽  
pp. 225-231 ◽  
Author(s):  
M. F. Lightstone ◽  
G. D. Raithby ◽  
K. G. T. Hollands
Keyword(s):  
Plug Flow ◽  
Energy System ◽  
Hot Water ◽  
Storage Tanks ◽  
Fluid Turbulence ◽  
Liquid Storage ◽  
Model Predictions ◽  
Future Work ◽  
Insight Into ◽  
Good Agreement

The degree of thermal stratification maintained in hot water storage tanks has a significant impact on the performance of a solar energy system. This paper presents an axisymmetric finite volume model analysis of the charging of a tank with hot water, and compares the predictions with experimental results from the literature. The results show the capabilities and deficiencies of such a modeling technique for this type of problem. The importance of inlet fluid turbulence to tank destratification is demonstrated and inclusion of a simple turbulence model is found sufficient to yield good agreement with measurement. The model predictions also provide insight into when a simple one-dimensional plug flow model will be adequate. In addition, the model is used to evaluate the effect during charging of heat conduction in the tank wall on the temperature field in the fluid. Recommendations are made regarding future work on the development of detailed numerical codes for simulating the charging of liquid storage tanks.

Buckling at the Top of a Fluid-Filled Tank During Base Excitation

1987 ◽  
Vol 109 (4) ◽  
pp. 374-380 ◽  
Author(s):  
S. Natsiavas ◽  
C. D. Babcock
Keyword(s):  
Computer Code ◽  
Base Excitation ◽  
Storage Tanks ◽  
Linear Combinations ◽  
Ground Acceleration ◽  
A Value ◽  
Liquid Storage ◽  
System Equations ◽  
Set Up ◽  
General Dynamic

An explanation is provided for the earthquake-induced damage observed at the top of liquid storage tanks. An analysis is developed and the results are compared with experimental work. The basic steps of the analysis, which is developed for the general dynamic response of fluid-filled tanks under horizontal ground excitation, are first presented. In this analysis, the structural displacements are expanded in appropriate series forms which involve both rigid body and flexible components. The latter components are expressed as linear combinations of terms, each of which is a product of a function with assumed spatial dependence and an unknown time-dependent function. These time functions are then determined from the solution of the fluid/structure system equations, which are set up by employing Hamilton’s principle. In the present work, results are obtained and compared with model tests carried out at Caltech, during which buckling was observed at the top of the tank under a known base excitation history. Computing analytically the corresponding pressure distribution and using the BOSOR computer code for the buckling computations, a value for the amplitude of the ground acceleration which results in buckling at the top of the tank is calculated. Good correlation with the test work is obtained.

Performance of cylindrical liquid storage tanks in Silakhor, Iran earthquake of March 31, 2006

2007 ◽  
Vol 40 (4) ◽  
pp. 173-182 ◽  
Author(s):  
Sassan Eshghi ◽  
Mehran S. Razzaghi
Keyword(s):  
Linear Time ◽  
Time History ◽  
Storage Tanks ◽  
Liquid Storage ◽  
History Analysis ◽  
History Of ◽  
Flexible Foundation ◽  
Theoretical Results ◽  
Strong Ground ◽  
Good Agreement

Several on-ground cylindrical liquid storage tanks experienced strong ground motion during the “Silakhor” earthquake of March 31, 2006 in western Iran, and some of the tanks suffered minor to moderate damage. In this study two of the affected tanks that were located close to the station of recording the time history of the earthquake were investigated. Responses of these tanks to the earthquake were estimated using published methods and also non-linear time history analysis, for both rigid foundation and flexible foundation assumptions. Theoretical results were compared and were generally in good agreement with the observed performance of tanks during the earthquake. For the broad tank uplift displacements observed from the earthquake matched quite closely the predictions of numerical analysis and some of the published methods, although there was a significant variation in the predictions of various methods. It was also shown that axial stresses in tank shells uplifting under earthquake are very dependent on the rigidity of the foundation.

An Analytical Model for Unanchored Fluid-Filled Tanks Under Base Excitation

1988 ◽  
Vol 55 (3) ◽  
pp. 648-653 ◽  
Author(s):  
S. Natsiavas
Keyword(s):  
Ground Motion ◽  
Bottom Plate ◽  
Rigid Foundation ◽  
Base Excitation ◽  
Storage Tanks ◽  
Cylindrical Tank ◽  
Hydrodynamic Problem ◽  
Liquid Storage ◽  
Ground System ◽  
Lift Off

A set of equations is derived describing the dynamic response of cylindrical liquid storage tanks under horizontal ground excitation. The structure consists of a flexible cylindrical tank with a roof and a bottom plate and rests on a flexible ground through a rigid foundation. Portion of the base of the tank may separate from and lift off the foundation during ground motion. The solution of the hydrodynamic problem is first found in closed form. Then, Hamilton’s principle is applied and the equations governing the behavior of the coupled fluid/structure/ground system are derived. During this procedure, the base uplifting is modeled by an appropriate rotational nonlinear spring placed between the base of the tank and the foundation.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

Virus Removal by Filtration

1982 ◽  
Vol 14 (4-5) ◽  
pp. 253-256
Author(s):  
N Sriramula ◽  
M Chaudhuri
Keyword(s):  
Experimental Data ◽  
Escherichia Coli ◽  
Cationic Polyelectrolyte ◽  
Electrokinetic Phenomena ◽  
Virus Removal ◽  
Bacterial Virus ◽  
Gravity Settling ◽  
And Diffusion ◽  
Model Virus ◽  
Good Agreement

An investigation was undertaken on the removal of a model virus, bacterial virus MS2 against Escherichia coli, by sand filtration using untreated, and alum or cationic polyelectrolyte treated media, and uncoagulated as well as alum coagulated influent. Data on discrete virus removal were satisfactorily accounted for by electrokinetic phenomena and diffusion. For virus in association with turbidity, filter coefficients computed from experimental data were in good agreement with those predicted by mechanical straining and gravity settling which were the dominant mechanisms for removal of the turbidity particles to which the viruses attached.

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