• Earthquakes and Structures
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• v.20 no.4
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• pp.405-415
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• 2021

Following the dynamic property analysis and elaboration, linear response spectrum analysis (RSA) and response history analysis (RHA) were conducted on a representative hyperbolic cooling towers (HCT) in present study. The seismic responses in tower shell were illustrated in detail, including the internal force amplitude, modal contribution, influence from damping ratio, comparison of results got from RSA and RHA and especially the latitude distributions of internal forces. The results show that the eigenmodes could be classified in a new method into four types according to their mode shapes and only the lateral bending modes and vertical stretching modes are meaningful for horizontal and vertical earthquake correspondingly. The bending modes and seismic deformation display the same feature which is global lateral bending accompanied by minute circular flow displacement of section. This feature also decides the latitude distributions of internal forces as sine or cosine. Moreover, the following method is also proposed for approximate estimation of internal force amplitudes without time-consuming response history analysis: getting the response spectrums of the selected ground accelerations and then comparing values of response spectrums at the natural period of first lateral bending mode because it is always prime dominant for horizontal seismic responses.

• Clinical Pain
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• v.20 no.2
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• pp.122-126
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• 2021

When a patient represents pain in foot, physician can easily overlook compression neuropathy of peripheral nerve as it is uncommon. Among nerve entrapment syndrome encountered in the foot, selective compression in lateral branch of deep peroneal nerve (DPN) is rare. We report a case of a patient with pain and dysesthesia in dorsolateral foot which turned out as lateral branch of deep peroneal nerve entrapment syndrome caused by talonavicular joint effusion. We would like to share diagnostic work up flow and conservative treatment courses. This case manifests the importance of the deep peroneal nerve and its branches in clinical setting of pain and ankle instability.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.431-436
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• 2001

Lateral confining effect due to the existence of the shear reinforcements in R.C. beam is investigate in a numerical way. For the purpose, a three dimensional constitutive model of concrete is developed based on the elasto-plasticity using non-associated plastic flow rule to control the excessive inelastic dilatancy. The plastic flow direction is determined based on the associated plastic flow direction in a way to adjust the directional angle between the two normal vector components along the hydrostatic and deviatoric axis in a meridian plane in which the loading function prescribed. The current formulation is combined with the four parameter elasto-plastic triaxial concrete model recently developed. The resulting elasto-plastic triaxial concrete model predicts the fundamental behaviors of concrete under different confining levels and the 4-points flexural test of a beam with shear reinforcements, compares with the experimental results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.5
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• pp.1330-1337
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• 1994

This study is to predict the lateral dispersion of the particles with time in a vertical pipe. Particle is released downward and located in the center of a pipe through which stationary, homogeneous turbulent air is flowing. We assume that gas turbulence velocities have a Gaussian probability density distribution and the presence of particle is not to alter turbulent structures. Particle trajectory is computed by numerically integrating the particle Lagrangian equation of motion, with a random sampling to determine the fluctuating air velocity experienced by each particle, which considered inertia effect and crossing-trajectories effect. The result shows characterestics of particle dispersion according to flow field condition and droplet size by using the parameters and scales, which expressed characterestics of flow field and particle. Predictions agree reasonably with experimental data.

• Progress in Superconductivity
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• v.6 no.1
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• pp.52-55
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• 2004

The inductive coupling theory in serially stacked $Bi_2$$Sr_2$$CaCu_2$$O_{8+x}$ intrinsic Josephson junctions predicts that the lattice structure of the Josephson vortices along the c axis gradually changes from the triangular to the rectangular lattice with increasing the vortex velocity. This lattice transition appears as voltage jumps or sub-branch splitting in the Josephson vortex-flow region of current-voltage characteristics (IVC). We report the IVC in external magnetic fields from 2 to 4 T. The stack, with the lateral size of 1.4${\times}$15 $u\m^2$, was fabricated by using the double-side cleaving technique. The sub-branches in the Josephson vortex-flow region, corresponding to a plasma propagation mode in serially coupled intrinsic Josephson junctions, were also observed in the range of 2∼4T. Switching from one branch to another in Josephson vortex-flow region suggests the structural transition of the moving Josephson vortex lattice.

• Water Engineering Research
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• v.3 no.4
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• pp.235-245
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• 2002

In this study, breakwater model which has several outlet pipes to discharge water is settled in the experimental open channel and mean velocity distributions of multi wall jet are measured. The length of flow of flow establishment of wall jet is shorter than that of free jet and decay rate of jet centerline longitudinal velocity along x is linear in 0.3 $\leq$ x/$\l_q$ $\leq$ 17. The rate of vertical width and lateral width spreading of multi wall jet is respectively 0.0753, 0.157~0.190.

• Water for future
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• v.24 no.1
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• pp.99-107
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• 1991

This study is for simulating to the model which analyzes flow characteristics and transverse bed slopes in a coarse-streambed of the meandering alluvial channels. Using the equations for conservation of mass, momentum, and for lateral stability of the streambed, a linear differential equation of transverse bed slope is derived from the flow characteristics in curved channels. Its solutions are solved by the Sine-generated curve method(SCM) and compared with results of field measurements. Lag distances by the maximum transverse bed slope and velocity profiles will predict risk sections of concave bank under floods.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.2
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• pp.148-155
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• 1995

For an accurate prediction of the temperature Held induced by surface discharge of heated water into an ambient cross-flow field. a three-dimensional near-field numerical model using k-$\varepsilon$ turbulence clousure is developed Rather restricted as it is, the numerical results of the model agree well with the experimental data. The developed model simulates quite adequately the stratification, gravitational lateral spreading, and upward entrainment of thermal jet which cannot be simulated by a depth-integrated two-dimensional numerical model, as well as the interaction with cross-flow.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.78-81
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• 2008

A numerical study of the unsteady flow in an over-expanded thrust optimized contour and compressed truncated perfect rocket nozzle is carried out in present paper. These rocket nozzles are subject to flow separation in transient phase at engine start-up and/or engine shut-down. The separation flow structures at different pressure ratios are observed. The start-up process exhibits two different shock structures such as FSS (Free Shock Separation) and RSS (Restricted Shock Separation). For a range of pressure ratios, hysteresis phenomenon occurs between these two separation patterns. A three-dimension compressible Navier-Stokes solver is used for the present study. One equation Spalart-Allmaras turbulence model is selected. The computed nozzle wall pressures show a good agreement with the experimental measurements. Present results have shown that present code can be used for the analysis of the transient flows in nozzle.

• Nuclear Engineering and Technology
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• v.52 no.9
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• pp.1945-1954
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• 2020

Subchannel code is one of the effective simulation tools for thermal-hydraulic analysis in nuclear reactor core. In order to reduce the computational cost and improve the calculation efficiency, empirical correlation of turbulent mixing coefficient is employed to calculate the lateral mixing velocity between adjacent subchannels. However, correlations utilized currently are often fitted from data achieved in central channel of fuel assembly, which would simply neglect the wall effects. In this paper, the CFD approach based on spectral element method is employed to predict turbulent mixing phenomena through gaps in 3 × 3 bare tight lattice rod bundle and investigate the flow pulsation through gaps in different positions. Re = 5000,10000,20500 and P/D = 1.03 and 1.06 have been covered in the simulation cases. With a well verified mesh, lateral velocities at gap center between corner channel and wall channel (W-Co), wall channel and wall channel (W-W), wall channel and center channel (W-C) as well as center channel and center channel (C-C) are collected and compared with each other. The obvious turbulent mixing distributions are presented in the different channels of rod bundle. The peak frequency values at W-Co channel could have about 40%-50% reduction comparing with the C-C channel value and the turbulent mixing coefficient β could decrease around 25%. corrections for β should be performed in subchannel code at wall channel and corner channel for a reasonable prediction result. A preliminary analysis on fluctuation at channel gap has also performed. Eddy cascade should be considered carefully in detailed analysis for fluctuating in rod bundle.