• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.6
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• pp.771-787
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• 1998

A Navier-Stokes code with a modified low Reynolds number k-.epsilon. turbulence model was used to study the unsteady transitional boundary layer flow due to rotor-stator interaction. The modification, proposed by Launder, to improve prediction of stagnation flows was incorporated to the low Reynolds number k-.epsilon. turbulence model by Fan-Lakshminarayana-Barnett. Numerical solution is shown to capture well the calmed laminar flow as well as the wake induced transitional strip due to rotor-stator interaction and shows improvement, in terms of onset of transition and its length, over previous Euler/boundary layer solution. The turbulent kinetic energy shows local maximum along the upstream rotor wake in the wake induced transitional strip and this characteristics is observed untill the end of transition. The wake induced strip also shown apparent even in the laminar sublayer as the upstream rotor wake penetrates inside the boundary layer.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.238-242
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• 2008

Transitional zones, one of the typical weak area of earthworks, require lasting a maintenance work due to a differential stiffness of substructures. It is very difficult problem that transition zone was perfectively prevented against a differential settlement. The transitional zone will deteriorate at an accelerate rate. This may lead to pumping ballast, swinging or hanging sleepers, permanent rail deformations, worn track components, and loss of surface and gauge. In this study, it is performed that settlement behavior in transitional zone was compared with small model test.

• Journal of computational fluids engineering
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• v.4 no.2
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• pp.17-30
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• 1999

The unsteady transitional boundary layer due to rotor-stator interaction was studied at two operation points, the design and one off design points. The off design point leads to lower blade loading and lower Reynolds number. A Navier-Stokes code developed in the previous study was parallelized to expedite computations. A low Reynolds number turbulence model was used to close the momentum equations. All computations show good agreement with experimental data. The wake induced transitional strip on the suction side of the stator is clearly captured at design point operation. There is no noticeable change in shape and phase angle of the wake induced strip even in the laminar sublayer. The wake induced transitional strip at off design point shows more complex structure. The wake induced transitional strip is observed only in the turbulent layer, and becomes obscure in the laminar sublayer and buffer layer. This behavior is probably consequent upon that the transition is governed by both wake induced strip and natural transition mechanism by Tollmien-Schlichting wave.

• Advances in aircraft and spacecraft science
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• v.4 no.5
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• pp.555-571
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• 2017

The description of transitional flows by means of RANS equations is sometimes based on non-local approaches which require the computation of some boundary layer properties. In this work a non-local Laminar Kinetic Energy model is used to predict transitional and separated flows. Usually the non-local term of this model is evaluated along the grid lines of a structured mesh. An alternative approach, which does not rely on grid lines, is introduced in the present work. This new approach allows the use of fully unstructured meshes. Furthermore, it reduces the grid-dependence of the predicted results. The approach is employed to study the transitional flows in the T106c turbine cascade and around a NACA0021 airfoil by means of a discontinuous Galerkin method. The local nature of the discontinuous Galerkin reconstruction is exploited to implement an adaptive algorithm which automatically refines the mesh in the most significant regions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.3
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• pp.202-211
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• 2017

In this study, numerical simulations were performed using the ${\gamma}-Re_{\theta}$ transition model of KFLOW for the transitional flow over the KARI-11-180 airfoil. Numerical results of KFLOW were compared with experimental data and two other numerical results of XFoil and MSES. Fully turbulence model was predicted high skin friction drag than transition model because fully turbulence model could not solve the transitional flow. Numerical predictions using the ${\gamma}-Re_{\theta}$ model of KFLOW show a good agreement with experimental data and other numerical results. Present numerical results were confirmed the state of drag bucket due to dramatic changing of the transition location on the airfoil surface.

• Korea journal of population studies
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• v.18 no.2
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• pp.51-69
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• 1995

The Swedish welfare state has been the model for others to emulate the archetypical example of state intervention. The state interventions are presented in the form of legal acts. These social welfare acts can be classified according to the demographic transition theory. According to the Bogue's theory, the demographic transition in Sweden took place in four stages : the pre-transitional stage before 1810; the early transitional stage from 1810 to 1860; the mid-transitional stage from 1860 to 1930; the late transitional stage from 1930 to now. As we look into the social welfare acts in Sweden, the relief of the poor was the major concern of the early transitional stage, the care of workers was the major concerns of the mid-transitional stage and the care of the families was the major concerns in the late transitional stage. The Korea's transition period can be devided as follows; the pre-transitional stage before 1960; the early transitional stage from 1960 to 1969; the mid-transitional stage from 1970 to 1987; and the late transitional stage from 1987 to now. In Korea, the major concern of the early transitional stage was the care of the officials and the workers; in the mid-transitional stage the care of the aged and the handicapped were the major concerns. And in the late transitional stage the expanding of the welfare clients was the major concern. If we compare the results of both countries, the relief of the poor, the care of the workers and the care of the families will be the major concerns in Korea, because the social welfare acts in Korea are extended to specific groups and not to the whole population. The acts related to these social issues have been arranged in 120 years in Sweden. But Korea had to do the same work in 27 years. So the burden of making those social acts will be four times heavier. If we want to extend the benefits of the social system to the general population, we need to look at the design and approach of the swedish model. The reason why swedish social acts constitute an international model has more to do with the uniqueness of its design and approach. First of all, it is characteristic by its universalism, secondly by its emphasis on social services and thirdly by its productivitism. Also the swedish welfare state supported by a high-tax system called the earnings-related welfare system. In order to achieve an effective welfare state, we Koreans should pay attention to the relief of the poor, the care of the worker and the families. We should also focus on a good system design and prepare appropriate budgets.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.6
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• pp.779-792
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• 1997

Flow characteristics are numerically investigated when a packet of waves consisting of a Tollmien-Schlichting wave and a pair of Squire waves evolves in a flat-plate laminar boundary layer using a large eddy simulation with a dynamic subgrid-scale model. Characteristics of early stage transitional boundary layer flow such as the .LAMBDA. vortex, variation of the skin friction and backscatter are predicted. Smagorinsky constants and the eddy viscosity obtained from the dynamic subgrid-scale model significantly change as the flow evolves. Far Field noise radiated from the transitional boundary layer shows the dipole and quadrupole characteristics owing to the wall shear stress and the Reynolds stresses, respectively.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.3
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• pp.533-548
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• 2011

This study examined the concern levels of primary school teachers regarding transitional education from early childhood phase to primary education. Concern Based Adoption Model (CBAM) instrument of Hall and Hord (2006) was used to survey 104 primary school teachers. The results indicated that the majority of respondents' concern level was at 'informational' level (stage 1). And first peak of concern level was at 'unconcerned' level (stage 0). The first-second peak analysis of stage 0 (unconcerned) group indicated that there were 5 types of groups and each had distinguished features. Finally there were statistical differences at the unconcerned stage by in-service training and career of the first-year class. A discussion of the limitations of this study and implications for teacher education programs and operational support systems were suggested.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1196-1202
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• 2004

To evaluate the unsteady motion in laterally berthing maneuver, it is necessary to estimate clearly the magnitudes and properties of hydrodynamic forces acting on ship hull in shallow water. A numerical simulation has been performed to investigate quantitatively the hydrodynamic force according to water depth for Wigley model using the CFD (Computational Fluid Dynamics) technique. By comparing the computational results with the experimental ones, the validity of the CFD method was verified. The numerical solutions successfully captured some features of transient flow around the berthing ship. The transitional lateral force in a state ranging from the rest to the uniform motion is modeled by using the concept of circulation.

• Journal of Korean Academy of Nursing
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• v.40 no.4
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• pp.599-609
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• 2010

Purpose: The purpose of this study was to develop and evaluate a transitional care program for patients discharged from military hospitals. The study consists of two phases: developing the program and evaluating its effectiveness. Methods: The conceptual framework used to guide the development of the program was Meleis's transition theory. A quasiexperimental design was employed for this study. Participants were recruited from patients discharged from one military hospital, 72 in the control group and 56 in the experiment group. Data were analyzed using SPSS WIN 12.0 program with chi-square, Fisher's exact test, independent t-test, and mixed model. Results: Participants in the transitional care program reported promoting a positive personal condition, and more healthy patterns of response in the first week after being discharged and a smoother discharge transition. Conclusion: The transitional care program developed for discharge patients from military hospital promoted discharge readiness and promoted smooth discharge transition.