• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.575-582
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• 2009

The optimum rotation speed of a desiccant rotor is studied theoretically based on a theoretical solution to the heat and mass transfer processes in the desiccant rotor. A simple correlation equation for the optimum rotation speed is derived to show the effects of various parameters including the thermo-physical properties, the geometric dimension, and the operating condition of the desiccant rotor. The theoretical result is compared with existing experimental data to validate the linearization and simplification included in the solution procedure. Based on the theoretical solution, the effects of major parameters on the optimum rotation speed are studied and the fundamental mechanism of the influences is investigated.

• Structural Engineering and Mechanics
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• v.16 no.1
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• pp.35-46
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• 2003

The histories and distributions of dynamic stresses in an orthotropic hollow cylinder under sinusoidal impact load are obtained by making use of eigenfunction expansion method in this paper. Dynamic equations for axially symmetric orthotropic problem are founded and results are carried out for a practical example in which an orthotropic hollow cylinder is in initially at rest and subjected to a dynamic interior pressure $p(t)=-{\sigma}_0(sin{\alpha}t+1)$. The features of the solution appear the propagation of the cylindrical waves. The other hand, a dynamic finite element solution for the same problem is also got by making use of structural software (ABAQUS) program. Comparing theoretical solution with finite element solution, it can be found that two kinds of results obtained by two different solving methods are suitably approached. Thus, it is further concluded that the method and computing process of the theoretical solution are effective and accurate.

• Tunnel and Underground Space
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• v.14 no.1
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• pp.16-25
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• 2004

As underground caverns have many advantages such as safety and operation, they can also be used for gas storage purpose. When liquefied gas is stored underground, the cryogenic temperature of the gas affects the stability of the storage cavern. In order to store the liquefied gas successfully, it is essential to estimate the exact temperature distribution of the rock mass around the caverns. The main purpose of this study is the development of theoretical solution to be able to estimate the temperature distribution around storage caverns and the assessment of the solution. In this study, a theoretical solution and a conceptual model for estimating two and three dimensional temperature distribution around the storage caverns are suggested. Based on the multi-dimensional transient heat transfer theory, the theoretical solution is successfully derived by assuming the caverns shape as simplified geometry. In order to assess the theoretical solution, by performing numerical experiments with this multi-dimensional model, the temperature distribution of the theoretical solution is compared with that of numerical analysis. Furthermore, the effects of the caverns size are investigated.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.487-490
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• 2008

A theoretical study is made of the flow in a confined cylindrical container with differential rotating top and bottom disks. Two kinds of theoretical solution for the azimuthal velocity were obtained: one is an exact solution of Bessel function type and the other is an approximate solution of exponential function type which comes from WKB approximation. Both theoretical solutions are shown to be self consistent with each other as well as a good agreement with previous studies. Moreover, in a range of relatively low Reynolds number, the obtained solution of Bessel function type shows better result than previous solutions.

• Geomechanics and Engineering
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• v.19 no.2
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• pp.141-151
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• 2019

A novel theoretical solution is presented for created (zero initial radius) cavity expansion problem based on CamClay model and considers the effect of initial anisotropic in-situ stress and drained conditions. Here the strain of this theoretical solution is small deformation in elastic region and large deformation in plastic region. The works for cylindrical and spherical cavities expanding in drained condition from zero initial radius are investigated. Most of the conventional solutions were based on the isotropic and undrained condition, however, the initial stress state of natural soil mass is anisotropy by soil deposition history, and drained cavity expansion calculation is closer to actual engineering in permeable soil mass. Finally, the parametric study is presented in order to the engineering significance of this work.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3443-3446
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• 2014

We present the solution of Klein Gordon equation with new generalized Morse-like potential using SUSYQM formalism. We obtained approximately the energy eigenvalues and the corresponding wave function in a closed form for any arbitrary l state. We computed the numerical results for some selected diatomic molecules.

• Geomechanics and Engineering
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• v.8 no.3
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• pp.441-460
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• 2015

A new theoretical approach for analysis of stress around a tensioned anchor in rock is presented in this paper. The solution has been derived for semi-infinite elastic rock and anchor and for plane strain conditions. The method considers both the anchor head bearing plate and its grouted bond length embedded in depth. The solution of the tensioned rock anchor problem is obtained by superimposing the solutions of two simpler but fundamental problems: A distributed load applied at a finite portion (bearing plate area) of the rock surface and a distributed shear stress applied at the anchor-rock interface along the bond length. The solution of the first problem already exists and the solution of the shear stress distributed along the bond length is found in this study. To acquire a deep understanding of the stress distribution around a tensioned anchor in rock, an illustrative example is solved and stress contours are drawn for stress components. In order to verify the results obtained by the proposed solution, comparisons are made with finite difference method (FDM) results. Very good agreements are observed for the teoretical results in comparison with FDM.

• Earthquakes and Structures
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• v.16 no.1
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• pp.1-9
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• 2019

To provide a simplified method for the base isolation design of LNG tanks, such as $16{\times}104m^3$ LNG tanks, we conducted a derivation and calculation example analysis of the dynamic response of the base isolation of LNG storage tanks, using dynamic response analysis theory with consideration of pile-soil interaction. The ADINA finite element software package was used to conduct the numerical simulation analysis, and compare it with the theoretical solution. The ground-shaking table experiment of LNG tank base isolation was carried out simultaneously. The results show that the pile-soil interaction is not obvious under the condition of base isolation. Comparing base isolation to no isolation, the seismic response clearly decreases, but there is less of an effect on the shaking wave height after adopting pile top isolation support. This indicates that the basic isolation measures cannot control the wave height. A comparison of the shaking table experiment with the finite element solution and the theoretical solution shows that the finite element solution and theoretical solution are feasible. The three experiments are mutually verified.

• Computers and Concrete
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• v.11 no.3
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• pp.223-236
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• 2013

Self-healing (SH) technology of cracking is becoming a promising solution to improve the durability of cement based composites. However, little formula are available in the literature on determining the size and dosage of the self-healing capsules. Supposed that SH capsules will be broken and activated when they met cracks, a theoretical solution is developed to calculate the appropriate length of SH capsules based on Buffon's needle model. Afterwards, a method to calculate the dosage of capsules was proposed in terms of stereological theory. The reliability of the above mentioned theoretical methods was verified by computer simulation. An experiment of self-healing in mortar was performed as well, by which the theoretical models were verified.

• Bulletin of the Society of Naval Architects of Korea
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• v.8 no.1
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• pp.53-66
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• 1971

The effect of reinforced circular hole in a flat plate under general biaxial loading conditions is considered. The reinforcement is achieved by attaching a circular ring of uniform rectangular cross section along the boundary of the hole. This investigation includes a theoretical solution and an experimental conformation. In the theoretical analysis, Gurney's method is used to obtain a solution for the stress distribution and the solution is expressed in a general form, so that it can be applicable to the case of general biaxial loading and general values of Poisson's ratios. In the experimental work a systematic series of photoelastic models, as shown in Fig.5 and Table 1, were analyzed on polariscope. The experimental results were in good agreement with the theoretical ones, as shown in Fig.8 and 9. The conclusions derived are as follows: 1) The theoretical results, given in Eq. $(1){\sim}(5)$, are sufficient in accuracy for the engineering design purpose. 2) The stress concentration factor decreases as the ratio n increases, but not significant beyond n=3. 3) The stress concentration factor increase as the ratio m increases, but not significant below m=0.7.