• Proceedings of the KSME Conference
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• 2001.11a
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• pp.166-173
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• 2001

Recommended seismic design guide for the flat bottom vertical-cylindrical oil storage tanks in KS B 6225 is presented. Under earthquake excitations, the hydrodynamic pressure exerted on the tank walls produces overturning moment which may cause either a failure of the anchors or a buckling of the tank shell near its base. The basis for establishing design loads due to hydrodynamic pressure is described including seismic zone risk map in Korea, zone coefficients and the essential facilities factor. This procedure for calculating applied compressive stress on the shell base subjecting to seismic load and for estimating the allowable buckling stress is described.

• 한국가시화정보학회:학술대회논문집
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• 2004.11a
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• pp.44-47
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• 2004

Vortexing might occur during draining from tanks which reduces the rate of outflow. This phenomenon has practical relevance in the fuel feed system in space vehicles and rockets. Due to environmental disturbances rotational motion can be generated in the liquid-propellant tank, which in turn can affect the rate of outflow to the engines. The phenomenon is initialized by rotating the fluid In the experimental tank. The dip quickly develops into a vortex with an air core, which extends to the bottom port, reducing the effective cross-sectional area of the drain outlet and consequently the flow rate. Flow characteristics are investigated using SPIV(Stereoscopic Particle Image Velocimetry) method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.551-555
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• 1997

IJnder earthquake excitations, the hydrodynamic pressure exerted on the flat bottom vertical-cylindrical oil storage tank walls produces overturning moment which may cause either a failure of the anchors or a buckling of the tank shell near its base. The basis for establishing design loads due to hydrodynamic pressure is described including seismic zone risk map in Korea. zone coefficients and the essential facilities factor. This procedure for calculating applied compressive stress on the shell base subjecting to seismic load and for estimating the allowable buckling stress is described. And seismic design program for the tanks is presented.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.8
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• pp.745-754
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• 2000

An experimental study has been carried out in order to investigate the heat storage characteristics for a latent heat storage tank with horizontal shell and tube type. The heat storage tank consists of cylindrical capsules with a staggered tube bank. The effects of flow rates and initial temperature differences on the melting time and heat storage rates are examined. It is found that the melting time decreases with increase of the flow rates and initial temperature differences. Results also show that the time-averaged overall heat transfer coefficients increase in proportion to the increase of flow rates and initial temperature differences.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.275-283
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• 1999

To predict the dynamic behavior of the cylindrical liquid storage tank subjected to seismic ground motion three dimesional analysis with liquid-structure interaction must be performed, In this study a three dimensional dynamic analysis method over the frequency domain using FE-BE coupling technique which combines the efficiency of the boundary elements for liquid with the versatility of the finite shell elements for tank. The liquid region is modeled using boundary elements which can counter the sloshing effect at free surface and the structure region the tank itself is modeled using the degenerated finite shell elements. At the beginning of the procedure the equivalent mass matrix of the liquid is generated by boundary elements procedure. Then this equivalent mass matrix is combined with the mass matrix of the structure to produce the global mass matrix in the equation of the motion of fluid-structure interaction problem In order to demonstrate the accuracy and validity of the developed method the numerical results re compared with the previous studies. Finally the effects of the fluid-structure interaction on the natural frequency and dynamic response of the system are analyzed.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.2
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• pp.98-107
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• 1985

In this thesis, the Sol-Air temperature distribution for the side-wall of a cylindrical cryogenic storage tank made of nonhomogenious composite layer was studied, in order to calculate the thermal load by Newton's cooling law, when the solar radiation was applied upon the side wall. In the analysis, the atmospheric slab was assumed to be horizontal and infinitely large, and the Sol -Air temperature, which was found by the Net- Radiation method considering the longwave radiation wi th surroundings, was used for boundary condition. Energy equation and boundary conditions were normalized by the defined reference- temperature, and solved. The solutions were developed by the Fourier cosine series. Then, the Sol-Air temperature distribution for the side-wall of LNG storage tank was calculated.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.1-8
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• 1999

The present paper describes an approximation for estimation of earthquake-induced hydrodynamic loads in rigid storage tank which accelerated in horizontal direction. The storage tank is vertically cylindrical, and the sectional shape may be circular, rectangular or irregular. The solution for harmonic excitation is studied based on velocity potential theory, and then the time domain solution for earthquake is obtained by using design response spectrum. As a result, earthquake load is influenced primarily by the inertia force of high frequency effective mass of the storage tank, responding to the characteristics of design response spectrum, tank sectional shape, and the ratio of tank base length to depth. Earthquake-induced hydrodynamic loads in rigid storage tank can be effectively obtained by using the high frequency approximation method in case of quite large, or small ratio of the tank base length to water depth.

• Journal of the Korean Society of Visualization
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• v.10 no.2
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• pp.14-19
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• 2012

An optical fiber probe system for measuring the local void fraction in the air-water two-phase flow was developed with a 1550 nm light source. Air was injected through a nozzle placed in the center of the bottom wall of a water-filled cylindrical tank. The optical fiber probe having a diameter of $125{\mu}m$ was sufficiently thin to resolve the air-water interface of the bubbly flows. To verify the performance of the optical fiber probe, the synchronized high speed visualization study using a high speed camera was carried out. Comparison between the optical signals and the instantaneous bubble diffraction images confirms that the optical fiber probe is very accurate to measure the void fraction in two-phase flows. The estimated bubble diameter and the rising velocity by the optical fiber probe have 1% and 5% of accuracy, respectively.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.5
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• pp.287-296
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• 2020

The wave-impact load on offshore structures can be divided into green-water and wave-slamming impact loads. These wave impact loads are known to have strong nonlinear characteristics. Although the wave impact loads are dealt with in the current classification rules in the shipping industry, their strong nonlinear characteristics are not considered in detail. Therefore, to investigate these characteristics, wave-impact loads induced by a breaking wave on a circular cylinder were analyzed. A model test was carried out to measure the wave-impact loads due to breaking waves in a two-dimensional (2D) wave tank. To generate a breaking wave, the focusing wave method was applied. A series of 2D tank tests under a horizontal wave impact was carried out to investigate the structural responses of the cylindrical structure, which were obtained from the measured model test data. According to the results, we proposed a structural damage-estimation procedure of an offshore tubular member due to a wave impact load. Furthermore, a recommended wave-impact load is suggested that considers the minimum required thickness of each member. From the experimental results, we found that the required minimum thickness is dependent on the impact pressure located in a three-dimensional space on the surface of a tubular member.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.3 s.234
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• pp.503-510
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• 2005

In this paper, the topology optimization of inner-wall stiffener of cylindrical containers for the use as a rocket fuel tank is presented. Such structures for space mission should have high stiffness against the buck]ins while their weight should be maintained low from the viewpoint of cost and performance. Therefore, in the present work the reciprocal of critical buckling load is adopted as an objective function and the total mass of stiffener is constrained to a prescribed value. Due to the restriction of computational resources a section of cylindrical container is topologically optimized and this result is repeated to obtain the full design. Also, for manufacturability the concept of periodic topology pattern in design domain is newly introduced. In the numerical examples, the results by the proposed approach are investigated and compared with those of isogrid design.