Study on the Predictive Evaluation Method of Nonlinear Sloshing Wave Crest Impact Load on the Roof of Cylindrical Tanks

2019 ◽  
Author(s):  
Hideyuki Morita ◽  
Tomoshige Takata ◽  
Hideki Madokoro ◽  
Hiromi Sago ◽  
Shinobu Yokoi ◽  
...  
Keyword(s):  
Wave Height ◽  
Seismic Isolation ◽  
Liquid Surface ◽  
Impact Load ◽  
Free Liquid Surface ◽  
Wave Crest ◽  
Long Period ◽  
Nonlinear Sloshing ◽  
Earthquake Motion ◽  
Cylindrical Tanks

Abstract When cylindrical tanks installed on the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the free liquid surface inside the tank called sloshing may occur. If high-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage of the tank roof or outflow of internal liquid of the tank. Therefore, it is important to predict the wave height of sloshing generated by earthquake motion. Sloshing is a type of vibration of free liquid surface, and if the sloshing wave height is small, it can be approximated with a linear vibration model. In this case, the velocity-response-spectrum method using velocity potential can estimate the sloshing wave height under earthquake motion. However, if the sloshing wave height increases, the sloshing becomes nonlinear, and necessary to evaluate the wave height using other methods such as numerical analysis. Design earthquake magnitude levels in Japan tend to increase in recent years, long-period components of earthquake wave which act on the sloshing wave height also increase instead of introducing seismic isolation mechanisms. To evaluate sloshing wave crest impact load acting on the roof of a tank, there are few applications which quantitatively evaluated the crest impact load of nonlinear sloshing. To construct a simple technique to evaluate the sloshing impact load considering the nonlinear sloshing wave height which acts on a flat roof of cylindrical tanks, it is proposed that flow diagram of evaluating the sloshing impact load which newly took into consideration the nonlinearity of sloshing and the dynamic amplification factor. The applicability of the technique was verified with the shaking table tests results for cylindrical tank and flow-analysis results.

Study on the Predictive Evaluation Method of Load Acting on the Roof and Internal Components of Cylindrical Tanks by Nonlinear Sloshing

2020 ◽  
Author(s):  
Hideyuki Morita ◽  
Tomoshige Takata ◽  
Hideki Madokoro ◽  
Hiromi Sago ◽  
Shinobu Yokoi ◽  
...  
Keyword(s):  
Wave Height ◽  
Seismic Isolation ◽  
Liquid Surface ◽  
Impact Load ◽  
Response Spectrum ◽  
Free Liquid Surface ◽  
Past Study ◽  
Long Period ◽  
Nonlinear Sloshing ◽  
Cylindrical Tanks

Abstract When cylindrical tanks installed in the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the free liquid surface inside the tank called sloshing may occur. If high-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage of the tank roof or outflow of internal liquid of the Tank. Therefore, it is important to predict the wave height of sloshing generated by earthquake motions. Sloshing is a type of vibration of free liquid surface, and if the sloshing wave height is small, it can be approximated with a linear vibration model. In this case, the velocity-response-spectrum method using velocity potential can estimate the sloshing wave height under earthquake motions. However, if the sloshing wave height increases, the sloshing becomes nonlinear, and necessary to evaluate the wave height using other methods such as numerical analysis. Design earthquake magnitude levels in Japan tend to increase in recent years, long-period components of earthquake wave which act on the sloshing wave height also increase instead of introducing seismic isolation mechanisms. To evaluate load acting on the internal components of cylindrical tanks by nonlinear sloshing, there are few applications which quantitatively evaluated the crest impact load of nonlinear sloshing. In order to evaluate the load acting on the internal components of cylindrical tanks, the range of applicability of the fluid flow analysis method which validated the analysis accuracy of impact load acting on the roof in a simple cylindrical tank in the past study (PVP2019-93442) is extended to cylindrical tanks with internal components.

Study on the Predictive Evaluation Method of Nonlinear Sloshing Wave Height of Cylindrical Tanks: Part 2 — Proposal and Examination of Applicability of the Predictive Evaluation Method

2018 ◽  
Author(s):  
Hiromi Sago ◽  
Hideyuki Morita ◽  
Tomoshige Takata ◽  
Hideki Madokoro ◽  
Hisatomo Murakami ◽  
...  
Keyword(s):  
Wave Height ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Liquid Surface ◽  
Free Liquid Surface ◽  
Evaluation Technique ◽  
Long Period ◽  
Nonlinear Sloshing ◽  
Cylindrical Tanks ◽  
Simple Evaluation

When cylindrical tanks installed on the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the free liquid surface inside the tank called sloshing may occur. If high-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage to the tank roof or outflow of internal liquid. Therefore, it is important to predict the wave height of sloshing generated by an earthquake input. Sloshing is vibration of the free liquid surface, and when the sloshing wave height is small, it can be approximated with a linear vibration model. In that case, the velocity-response-spectrum method using velocity potential can estimate the sloshing wave height under an earthquake input. However, when the sloshing wave height increases and the sloshing becomes nonlinear, it is necessary to evaluate the wave height using other methods such as numerical analysis. Taking into consideration that design earthquake levels tend to increase and the use of seismic isolation mechanisms has continued to spread in recent years, the amplitude of the long-period components of an earthquake input which act on cylindrical tanks may also increase. Therefore, although the evaluation of nonlinear sloshing wave height is important, there are few examples which quantitatively evaluate the wave height of nonlinear sloshing. The purpose of this study is to construct a simple evaluation technique of a nonlinear sloshing wave height of cylindrical tanks. In this study, the simple evaluation technique of the nonlinear sloshing wave height was proposed based on the study result shown by the 1st report (PVP2018-84416). Moreover, in order to verify the applicability of the proposed evaluation technique, the shaking table test and flow analysis which used the small cylindrical tank were carried out. As a result, the applicability of the proposed evaluation technique has been verified.

Fundamental Study on Evaluation Method of Nonlinear Sloshing Wave Height of Cylindrical Tanks

2017 ◽  
Author(s):  
Hideyuki Morita ◽  
Tomosige Takata ◽  
Hideki Madokoro ◽  
Hiromi Sago ◽  
Hisatomo Murakami ◽  
...  
Keyword(s):  
Wave Height ◽  
Liquid Surface ◽  
Flow Analysis ◽  
Vof Method ◽  
Free Liquid Surface ◽  
Evaluation Technique ◽  
Long Period ◽  
Nonlinear Sloshing ◽  
Cylindrical Tanks ◽  
Simple Evaluation

When cylindrical tanks installed in the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the free liquid surface inside the tank called sloshing may occur. If high-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage to the tank roof or outflow of internal liquid. Therefore, it is important to predict the wave height of sloshing generated by an earthquake input. Sloshing is vibration of the free liquid surface, and when the sloshing wave height is small, it can be approximated with a linear vibration model. In that case, the velocity-response-spectrum method using velocity potential can estimate the sloshing wave height under an earthquake input. However, when the sloshing wave height increases and the sloshing becomes nonlinear, it is necessary to evaluate the wave height using other methods such as numerical analysis. Taking into consideration that design earthquake levels tend to increase and the use of seismic isolation mechanisms has continued to spread in recent years, it is possible that the long-period components of an earthquake input which act on cylindrical tanks will also increase. Therefore, although it is thought that the evaluation of nonlinear sloshing wave height is important, there are few examples which quantitatively evaluate the wave height of nonlinear sloshing. In this study, as a simple evaluation technique of a nonlinear sloshing wave height, the applicability of the correction coefficient proposed by Shimada et al. was examined based on the flow analysis which used Volume of Fluid (VOF) method. Moreover, it was studied that the VOF method can be used to evaluate nonlinear sloshing wave height and sloshing wave crest impact pressure acting on the fixed roof of a tank. Shaking table tests will continue to be carried out in order to verify the applicability of the simple evaluation technique of nonlinear sloshing wave height. Results from flow analysis code will also be validated against these test results.

Study on the Predictive Evaluation Method of Nonlinear Sloshing Wave Height of Cylindrical Tanks: Part 1 — Shaking Table Test Results and Verification Results of Analytical Method for Nonlinear Sloshing

2018 ◽  
Author(s):  
Hideyuki Morita ◽  
Tomoshige Takata ◽  
Hideki Madokoro ◽  
Hiromi Sago ◽  
Hisatomo Murakami ◽  
...  
Keyword(s):  
Wave Height ◽  
Shaking Table Test ◽  
Liquid Surface ◽  
Flow Analysis ◽  
Shaking Table ◽  
Test Results ◽  
Long Period ◽  
Nonlinear Sloshing ◽  
Analysis Technique ◽  
Cylindrical Tanks

When cylindrical tanks installed on the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the free liquid surface inside the tank called sloshing may occur. If high-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage to the tank roof or outflow of internal liquid. Therefore, it is important to predict the wave height of sloshing generated by an earthquake input. Sloshing is vibration of the free liquid surface, and when the sloshing wave height is small, it can be approximated with a linear vibration model. In that case, the velocity-response-spectrum method using velocity potential can estimate the sloshing wave height under an earthquake input. However, when the sloshing wave height increases and the sloshing becomes nonlinear, it is necessary to evaluate the wave height using other methods such as numerical analysis. Taking into consideration that design earthquake levels tend to increase and the use of seismic isolation mechanisms has continued to spread in recent years, the amplitude of the long-period components of an earthquake input which act on cylindrical tanks may also increase. Therefore, although the evaluation of nonlinear sloshing wave height is important, there are few examples which quantitatively evaluate the wave height of nonlinear sloshing. The purpose of this study is to construct a simple evaluation technique of a nonlinear sloshing wave height of cylindrical tanks. In this study, the shaking table test using the small cylindrical tank for studying the behavior of nonlinear sloshing was carried out. Furthermore, verification of the flow-analysis technique described by previous report (PVP2017-65313) was carried out by comparing with test results. As a result, the data for constructing an evaluation technique has been acquired. Moreover, the validity of the flow-analysis technique was has been verified.

scholarly journals The sloshing law of liquid surface for ground rested circular RC tank under unidirectional horizontal seismic action

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Lin Gao ◽  
Mingzhen Wang
Keyword(s):  
Seismic Response ◽  
Wave Height ◽  
Seismic Design ◽  
Liquid Surface ◽  
Damping Ratio ◽  
Liquid Sloshing ◽  
Seismic Action ◽  
Dynamic Coefficient ◽  
Established Method ◽  
Long Period

Abstract The dynamic characteristics and liquid sloshing of a circular tank are analysed using ADINA software through seismic response analyses. The maximum sloshing wave height for the circular tank under unidirectional horizontal seismic action is developed. The calculation method involves three parameters such as tank radius, seismic coefficient and dynamic coefficient. The dynamic coefficient of liquid sloshing is determined corresponding to the long-period seismic design β spectrum with a 5% damping ratio using basic sloshing period. The established method can guide the seismic design of liquid-containing structures. The established method of calculating sloshing wave height is compared with those in the American code.

scholarly journals Estimation of long period response spectra with nonlinear sloshing analysis of cylindrical tanks.

1986 ◽  
pp. 383-392 ◽  
Author(s):  
Saburo SHIMADA ◽  
Yoshikazu YAMADA ◽  
Hirokazu IEMURA ◽  
Shigeru NODA
Keyword(s):  
Response Spectra ◽  
Long Period ◽  
Nonlinear Sloshing ◽  
Cylindrical Tanks

Study on the Predictive Evaluation Method for Liquid Surface Shape and Flow Velocity in Nonlinear Sloshing Based on Simplified Equations

2020 ◽  
Author(s):  
Shunichi Ikesue ◽  
Hideyuki Morita ◽  
Tomoshige Takata ◽  
Hideki Madokoro ◽  
Hidekazu Ishii ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Wave Height ◽  
Seismic Waves ◽  
Evaluation Method ◽  
Liquid Surface ◽  
Input Parameter ◽  
Surface Shape ◽  
Surface Velocity ◽  
Linear Potential ◽  
Nonlinear Sloshing

Abstract When cylindrical tanks installed in the ground, such as oil tanks and liquid storage tanks, receive strong seismic waves, including the long-period component, motion of the liquid surface inside the tank called sloshing may occur. If large-amplitude sloshing occurs and the waves collide with the tank roof, it may lead to accidents such as damage of the tank roof or outflow of internal liquid of the tank. Also, there is a possibility that the internal components in the tank may be damaged due to the fluid force generated by the flow of the sloshing. In order to evaluate the load acting on the tank roof, it is considered that the liquid surface shape and the liquid surface velocity are required as input parameters. In order to evaluate the load acting on the internal component in the tank, the flow velocity generated by sloshing is required as an input parameter. If the sloshing wave height is small, these values can be calculated based on the linear potential theory. However, when the sloshing wave height increases, the sloshing becomes nonlinear, and the difference between the nonlinear sloshing behavior and the linear sloshing behavior. Therefore, the method of evaluating nonlinear sloshing behavior is necessary to evaluate the design load of tank under the large sloshing wave height condition. In this paper, new methods of evaluating nonlinear sloshing behavior are proposed for the first-order sloshing mode of a cylindrical tank, which can evaluate the maximum nonlinear sloshing wave height, the nonlinear liquid surface shape, the liquid surface velocity, and the flow velocity. Proposed methods, which consist of simplified equations, are expected to be applied to a new sloshing load evaluation method in primary design.1

Isolation Performance of Intelligent Seismic Isolation System Using Air Bearing

2009 ◽  
Author(s):  
Satoshi Fujita ◽  
Keisuke Minagawa ◽  
Mitsuru Miyazaki ◽  
Go Tanaka ◽  
Toshio Omi ◽  
...  
Keyword(s):  
Seismic Isolation ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Air Bearings ◽  
Natural Period ◽  
Isolation System ◽  
Vertical Excitation ◽  
Long Period ◽  
Isolation Performance

This paper describes three-dimensional isolation performance of seismic isolation system using air bearings. Long period seismic waves having predominant period of from a few seconds to a few ten seconds have recently been observed in various earthquakes. Also resonances of high-rise buildings and sloshing of petroleum tanks in consequence of long period seismic waves have been reported. Therefore the isolation systems having very long natural period or no natural period are required. In a previous paper [1], we proposed an isolation system having no natural period by using air bearings. Additionally we have already reported an introduction of the system, and have investigated horizontal motion during earthquake in the previous paper. It was confirmed by horizontal vibration experiment and simulation in the previous paper that the proposed system had good performance of isolation. However vertical motion should be investigated, because vertical motion varies horizontal frictional force. Therefore this paper describes investigation regarding vertical motion of the proposed system by experiment. At first, a vertical excitation test of the system is carried out so as to investigate vertical dynamic property. Then a three-dimensional vibration test using seismic waves is carried out so as to investigate performance of isolation against three-dimensional seismic waves.

scholarly journals Wave Force Characteristics of Large-Sized Offshore Wind Support Structures to Sea Levels and Wave Conditions

2019 ◽  
Vol 9 (9) ◽  
pp. 1855
Author(s):  
Youn-Ju Jeong ◽  
Min-Su Park ◽  
Jeongsoo Kim ◽  
Sung-Hoon Song
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Wave Force ◽  
Diffraction Effect ◽  
Support Structures ◽  
Sea Levels ◽  
Irregular Wave ◽  
Long Period ◽  
Short Period ◽  
Period Wave

This paper presents the results of wave force tests conducted on three types of offshore support structures considering eight waves and three sea levels to investigate the corresponding wave forces. As a result of this study, it is found that the occurrence of shoaling in shallow water induces a significant increase of the wave force. Most of the test models at the shallow water undergo a nonlinear increase of the wave force with higher wave height increasing. In addition, the larger the diameter of the support structure within the range of this study, the larger the diffraction effect is, and the increase in wave force due to shoaling is suppressed. Under an irregular wave at the shallow water, the wave force to the long-period wave tends to be slightly higher than that of the short period wave since the higher wave height component included in the irregular wave has an influence on the shoaling. In addition, it is found that the influence of shoaling under irregular wave becomes more apparent in the long period.

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