• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.524-529
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• 2010

In the present study, a CFD program is developed for the Fluid-Structure Interaction(FSI) analysis. The non-staggered, non-orthogonal, and unstructured grid system was also used to handle the complicated geometries in the program. In order to validate the capabilities of the developed CFD program, various models are investigated by using unstructured and nonorthogonal meshes. The predicted results are a good agreement with analytic solution, experimental data and commercial software. And also PISO algorithm is applied for transient flow analysis. The cyclic boundary condition and baffle cell are developed in order to improve the effectiveness of the calculation for complex geometry.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1174-1179
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• 2000

In recent years, the structural shock response to underwater explosion has been studied as much, or more, through numerical simulations than through testing for several reasons. Very high costs and sensitive environmental concerns have kept destructive underwater explosion testing to a minimum. Increase of simulation capabilities and sophisticated simulation tools has made numerical simulations more efficient analysis methods as well as more reliable testing aids. For the simulation of underwater explosions against, surface ships or submerged structures one has to include the effects of the explosive shock wave, the motion of the gaseous reactive products, the local cavitation collapse, the different nonlinear structural properties and the complex fluid-structure interaction phenomena. In this study, as benchmark step for the validation of hydrocode LS/DYNA3D and of technology of fluid-structure interaction problems, two kinds of cavitation problems are analyzed and structural shock response of floating ship model are compared with experimental result.

• 한국해양공학회지
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• 제31권1호
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• pp.22-27
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• 2017

This paper presents the results of an experimental study on the wedge slamming impact problem, including the fluid-structure interaction. A free drop test was performed to estimate the hydroelasticity. Three wedges were fabricated of 5 mm thick steel plate. The deadrise angles were $15^{\circ}$, $20^{\circ}$, and $25^{\circ}$. Plate thicknesses of 2 mm and 3 mm were used to determine the effect of the structural rigidity. The drop heights were 25 cm, 50 cm, 75 cm, and 100 cm. The pressure on a rigid part of the wedge and strain of the elastic plate were measured at four different locations. The pressure was compared using the Wagner theory and generalized Wagner theory.

• 한국해양공학회지
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• 제34권2호
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• pp.120-127
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• 2020

Evaluation of fatigue strength considering the springing effect of very large container ships is crucial in the design stage. In this study, we established a fatigue strength evaluation method considering a linear springing component in the frequency domain. Based on a three-dimensional global model, a fluid-structure interaction analysis was performed and the modal superposition method was applied to determine the hot spot stress at the hatch corner of very large container ships. Fatigue damage was directly estimated using the stress transfer function with a linear springing response. Furthermore, we proposed a new methodology to apply the springing effect to fatigue damage using hull girder loads. Subsequently, we estimated the fatigue damage contribution due to linear springing components along the ship length. Finally, we discussed the practical application of the proposed methods.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.159-168
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• 2005

Noise generated by the blunt trailing edge of lifting surfaces is investigated in this study using fluid structure interaction theory. First, through the eddy modeling, noise generation doe to the flow instability on the rigid trailing edge is surveyed. Then the behavior of elastic cantileverd beam is investigated. Parametric study based on various material properties is employed to analyze the motion of the beam. Moreover, each eigenmode approach of cantilevered beam is used to find when flow induced vibration is resonant. To analyze elastic behavior of cantilever beam efficiently, moving grid generation technique based on non-conservative form of Navier-Stokes equation is used. Equation of the motion associated with the cantilever beam is discretized by the Galerkin procedure with forced vibration. As a consequence, behavior of the elastic cantilevered beam is stable when the first mode natural frequency of the material is relatively higher than that of flow induced pressure fluctuation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1487-1491
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• 2008

Detailed knowledge on the motion of blood cells flowing in micro-channels under simple shear flow and the influence of blood flow is essential to provide a better understanding on the blood rheological properties and blood cell aggregation. The microscopic behavior of red blood cell (RBCs) is numerically investigated using a fluid-structure interaction (FSI) method based on the Arbitrary-Lagrangian-Eulerian (ALE) approach and the dynamic mesh method (smoothing and remeshing) in FLUENT (ANSYS Inc., USA). The employed FSI method could be applied to the motions and deformations of a single blood cell and multiple blood cells, and the primary thrombogenesis caused by platelet aggregation. It is expected that, combined with a sophisticated large-scale computational technique, the simulation method will be useful for understanding the overall properties of blood flow from blood cellular level (microscopic) to the resulting rheological properties of blood as a mass (macroscopic).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.408-409
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• 2008

This paper presents a new development for topology optimization of heat-dissipating structure with forced convection. To cool down electric devices or machines, two types of convection models have been widely used: Natural convection model with a large Archimedes number and Forced convection with a small Archimedes number. Nowadays, many engineering application areas such as electrochemical conversion device or fuel cell devices adopt the forced convection to transfer generated heat. Therefore, to our knowledge, it becomes an important issue to design flow channels inside which generated heat transfer. Thus, this paper studies optimal topological designs considering fluid-heat interaction. To consider the effect of the advection in the heat transfer problem, the incompressible Navier-stokes equation is solved. This paper numerically studies the coupling phenomena and presents optimal channel design considering forced convection.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.729-734
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• 2008

A thermal stratification may occur in the horizontal parts of the surge line during operating transients of the pressurizer, which produces relatively high fatigue usage factor. Heat-up transient is the most severe case among the transient conditions. In this study, to study the relationship between the magnitude of thermal stratification and the length of vertical part of the surge line, some parametric fluid-structure interaction (FSI) analyses with different length variables of the vertical part of the surge line were performed for plant heat-up transient condition by using 3-dimensional numerical analysis. The conservativeness of the traditional finite element model for thermal stratification analysis based on the conservative assumption in the surge line was also discussed by comparison of the results of 3-dimensional transient FSI analysis of this study. Stresses calculated with 3-dimensional transient model were considerably reduced comparing with the traditional analysis.

• 동력기계공학회지
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• 제8권4호
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• pp.49-56
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• 2004

To design very large ships, such as very large drillships, we have to estimate the hydroelastic responses of the very large ships in waves. A numerical procedure is described for estimating the hydroelastic responses of very large ships advancing with slow speed in waves. The developed numerical approach is based on a combination of the three-dimensional source distribution method and the finite element method, including fluid-structure interaction by regarding a very large ship as many hull elements connected with elastic beam elements. Numerical results are compared with experimental and numerical ones obtained in the literature. The results of comparison confirmed the validity of the proposed approach.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.284-284
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• 2003

The free vibration characteristics of the cylindrical shell submerged in water is investigated using by FEM and experiment. In the FE analysis, the fluid-structure interaction effect is concerned. The restraint condition is clamped-free. In the results, the natural frequency and mode shape characteristics are evaluated with various water height. This results are compared with those of experiment to verify the validation of the FE analysis. The change of damping ratio is also presented by experiment.