• Journal of applied mathematics & informatics
• /
• 제8권1호
• /
• pp.59-69
• /
• 2001

The paper deals with the interaction between three Griffith cracks propagating under antiplane shear stress at the interface of two dissimilar infinite elastic half-spaces. The Fourier transform technique is used to reduce the elastodynamic problem to the solution of a set of integral equations which has been solved by using the finite Hilbert transform technique and Cooke’s result. The analytical expressions for the stress intensity factors at the crack tips are obtained. Numerical values of the interaction efect have been computed for and results show that interaction effects are either shielding or amplification depending on the location of each crack with respect to other and crack tip spacing. AMS Mathematics Subject Classification : 73M25.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년도 학술대회
• /
• pp.57-70
• /
• 2008

A high-order accurate Euler flow solver based on a discontinuous Galerkin finite-element method has been developed for the numerical simulations of blade-vortex interaction phenomena on unstructured meshes. A free vortex in freestream was investigated to assess the vortex-preserving property and the accuracy of the present flow solver. Blade-vortex interaction problems in subsonic and transonic freestreams were simulated by adopting a multi-level solution-adaptive dynamic mesh refinement/coarsening technique. The results were compared with those of other numerical and experimental methods. It was shown that the present discontinuous Galerkin flow solver can preserve the vortex structure for significantly longer vortex convection time and can accurately capture the complex unsteady blade-vortex interaction flows, including generation and propagation of acoustic waves.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2008년 추계학술대회논문집
• /
• pp.57-70
• /
• 2008

A high-order accurate Euler flow solver based on a discontinuous Galerkin finite-element method has been developed for the numerical simulations of blade-vortex interaction phenomena on unstructured meshes. A free vortex in freestream was investigated to assess the vortex-preserving property and the accuracy of the present flow solver. Blade-vortex interaction problems in subsonic and transonic freestreams were simulated by adopting a multi-level solution-adaptive dynamic mesh refinement/coarsening technique. The results were compared with those of other numerical and experimental methods. It was shown that the present discontinuous Galerkin flow solver can preserve the vortex structure for significantly longer vortex convection time and can accurately capture the complex unsteady blade-vortex interaction flows, including generation and propagation of acoustic waves.

• Nuclear Engineering and Technology
• /
• 제55권5호
• /
• pp.1855-1862
• /
• 2023

Graphite crucibles are used for melting uranium and its alloys in VIM furnace. Various coating materials namely Al₂O₃, ZrO₂, MgO etc. are applied on the inner surface of the crucibles using paint brush or thermal spray technique to mitigate U-C interaction. These leads to significant amount of carbon pick-up in uranium. In this study, the attempts are made to develop multilayer coatings comprising of SiC/Y₂O₃ and Mo/Y₂O₃ on graphite to study the feasibility of minimizing U-C interaction. The parameters are optimized to prepare SiC coating of about 70㎛ thickness using CVD technique on graphite coupons and subsequently Y₂O₃ coating of about 250㎛ thickness using plasma spray technique. Molybdenum and Y₂O₃ layers were deposited using plasma spray technique with 70㎛ and 250㎛ thickness, respectively. Interaction studies of the coated graphite with molten uranium at 1450℃ for 20 min revealed that Y₂O₃ coating with SiC interlayer provides physical barrier for uranium-graphite interaction, however, this led to the physical separation of coating layer. Y₂O₃ coating with Mo interlayer provided superior barrier effect showing no degradation and the coatings remained intact after interaction tests. Therefore, the Mo/Y₂O₃ coating was found to be a promising solution for minimizing carbon pick-up during uranium/uranium alloy melting.

• 비파괴검사학회지
• /
• 제11권1호
• /
• pp.7-12
• /
• 1991

The multi-frequency eddy current technique has been used for evaluation of various type of defects in tubings. However, this technique is not sufficient to detect and evaluate the defect in tubings if the defect is located in the geometrically complicated area(e. g. tube support plate, anti-vibration bar, tubesheet area) and mixing residue signal is significant to the defect signal. In order to improve the reliability of the multi-frequency eddy current technique, the effect of the interaction of mixing residue after frequency mixing with a function of distances between the defect and the tube support plate boundary has been analyzed theoretically. The experimental results have been discussed with the theoretical developments. The calculation shows the interaction between the two neighboring signal sources could be significant within the range of approximately 1.0mm with the experimental condition.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2003년도 추계 학술대회논문집
• /
• pp.188-193
• /
• 2003

The present work solved 3D incompressible RANS equation on a rotating, non-orthogonal multi-blocked grid system to efficiently analyze ducted marine propulsor with rotor-stator interaction. To handle the interface boundary between a rotor and a stator maintaining the conservative property, the sliding multiblock technique using the cubic spline interpolation and the bilinear interpolation technique were applied. To validate present code, a turbine flow having rotor- stator interaction was simulated. Time averaged pressure coefficients were compared with experiments and good agreement was obtained. After the code validation, the flowfield around a single-stage ducted marine propulsor was simulated.

• 한국가시화정보학회지
• /
• 제15권1호
• /
• pp.32-40
• /
• 2017

Interaction between fluid and a rigid object is frequently observed in everyday life. However, it is difficult to simulate their interaction as the medium and the object have different representations. One of the challenging issues arises especially in handling deformation of the object visually as well as rendering haptic feedback. In this paper, we propose a real-time simulation technique for multimodal interaction between particle-based fluids and soluble solids. We have developed the dissolution behavior model of solids, which is discretized based on the idea of smoothed particle hydrodynamics, and the changes in physical properties accompanying dissolution is immediately reflected to the object. The user is allowed to intervene in the simulation environment anytime by manipulating the solid object, where both visual and haptic feedback are delivered to the user on the fly. For immersive visualization, we also adopt the screen space fluid rendering technique which can balance realism and performance.

• 한국자기공명학회논문지
• /
• 제22권4호
• /
• pp.125-131
• /
• 2018

Chemical shift perturbation (CSP) is a simple NMR technique for studying binding of a protein to various ligands. CSP is the only technique that can directly provide both a value for the dissociation constant and a binding site from the same set of measurements. To accurately analyze the CSP data, the exact binding mode such as multiple binding, should be carefully considered. In this review, we analyzed systematically the CSP data with multiple modes. This analysis might provide insight into the mechanism on how proteins selectively recognize their target ligands to achieve the biological function.

• Geomechanics and Engineering
• /
• 제5권4호
• /
• pp.283-297
• /
• 2013

The aim of this paper is to investigate how the soil-structure interaction affects sloshing response of the elevated tanks. For this purpose, the elevated tanks with two different types of supporting systems which are built on six different soil profiles are analyzed for both embedded and surface foundation cases. Thus, considering these six different profiles described in well-known earthquake codes as supporting medium, a series of transient analysis have been performed to assess the effect of both fluid sloshing and soil-structure interaction (SSI). Fluid-Elevated Tank-Soil/Foundation systems are modeled with the finite element (FE) technique. In these models fluid-structure interaction is taken into account by implementing Lagrangian fluid FE approximation into the general purpose structural analysis computer code ANSYS. A 3-D FE model with viscous boundary is used in the analyses of elevated tanks-soil/foundation interaction. Formed models are analyzed for embedment and no embedment cases. Finally results from analyses showed that the soil-structure interaction and the structural properties of supporting system for the elevated tanks affected the sloshing response of the fluid inside the vessel.

• 정보과학회 컴퓨팅의 실제 논문지
• /
• 제22권8호
• /
• pp.357-362
• /
• 2016

소셜 네트워크나 바이오 네트워크는 인터랙션이 가능한 오브젝트들이 관계를 맺음으로써 형성되는 복잡 네트워크이다. 실세계에 존재하는 복잡 네트워크는 커뮤니티 구조로 구성되어 있으며, 이 커뮤니티 구조를 자동으로 발견하는 것은 그 네트워크를 제어하고 이해하는데 있어서 중요한 기술이다. 하지만 이런 네트워크들은 시간에 따라 오브젝트들의 인터랙션에 의해 그 네트워크의 구조와 위상이 불특정하게 변화한다. 이런 동적 네트워크에서 노드들 간에 인터랙션을 기반으로 한 커뮤니티 구조를 발견하는 것은 높은 시간 복잡도 연산이 요구되며, 반복된 계산을 비효율적으로 처리하는 문제점이 있다. 따라서 본 연구에서는 동적 네트워크에서 인터랙션 기반 커뮤니티 구조를 점진적으로 발견하는 기법을 제안한다. 제안하는 기법은 이전 네트워크에서 변화한 요소들을 인지하고, 이전 커뮤니티 그룹 구조를 점진적으로 재활용함으로써 효율적인 커뮤니티 발견이 가능하다.