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COMPARISON STUDY FOR FRONT-TRACKING NUMERICAL METHODS IN 1D GEOMETRY
Dongyung KIM 한국산업응용수학회 2009 한국산업응용수학회 학술대회 논문집 Vol.4 No.2
We compare several compressible fluid dynamics codes in a 1D geometry suggestive of an inertial confinement fusion (ICF) application. We study several algorithms and conduct a systematic mesh refinement study. The principal difficulty in the test problem selected is a strong shock passage through two narrowly spaced density layers, leading to multiple reflected waves. On account of these difficulties, numerical convergence requires extensive mesh refinement. Such refinement is within reach in 1D, which thus provides a convenient testing platform for the convergence requirements which would not practical for a 2D or 3D simulations. The codes compared are FronTier, RAGE and PROMETHEUS, and within this framework, we compare a variety of algorithms, including PPM, TVD, Godunov-split and MUSCL. We explore both tracked and untracked simulations, where the tracking (if applied) is limited to the initially defined density discontinuities. Our first main conclusion is the overall similarity of the convergence properties. Within this similarity, we note several trends. FronTier excels on moderate grids, while PPM excels on very fine ones.
An exact solution of location of a circle to a set of the weighted points
Dongyung Kim,Seonjeong LEE,Dongwoo Sheen 한국산업응용수학회 2010 한국산업응용수학회 학술대회 논문집 Vol.5 No.1
We consider the minimax problems of location of the circle to a set of the weighted points with passing through the two fixed points. The problem can be applied to design of nano-scale circuits and facility location. We suggested the problem properties and the solution procedure. Finally, we resolved to find an exact solution of location of a circle with the suggested constraints and posted the numerical computation time with the number of points.
인-휠 후륜구동 전기자동차의 독립구동 제어를 이용한 선회 성능 향상에 관한 연구
최민석(Minseok Choi),김창준(Changjun Kim),김동형(Dongyung Kim),김상호(Sangho Kim),최주영(Jooyoung Choi),한창수 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
With the recent advancement of control method and battery technology, the electric vehicle have been researched to replace the conventional vehicle with electric vehicle with the view point of the environmental concerns and energy conservation. An electric vehicle which is equipped with the in-wheel motors has some advantages in terms of control. For example, the different torque which generated by left and right wheels directly can make yaw moment of vehicle with steering angle and it can improve the vehicle stability in cornering. This is called direct yaw moment control. In this paper, we consider a method for improving the stability of In-wheel motored electric vehicle with the direct yaw moment control. We also apply yaw moment observer to estimate the moment generated by the tire and the road contact. Simulation results show that the method can improve the stability of In-wheel motored electric vehicle in cornering.
황을 포함한 유기화합물인 NaDDTC의 CuNi합금에 대한 화학적 흡착에 관한 정량적 분석
정길봉,김동영,장요한,Jung, Gilbong,Kim, Dongyung,Jang, Yohan 한국군사과학기술학회 2015 한국군사과학기술학회지 Vol.18 No.5
This paper is results on Chemisorption of organic compound for the sea water fire fighting line of naval vessels. The quantitative analysis of Chemisorption has been investigated in seawater after immersion in 0.1 % of NaDDTC solutions for 43 hours. The morphology and topography were investigated by FE-SEM and AFM. The chemical elements were analyzed by SEM-EDS, XPS and the depth of chemical elements was measured by depth profiles. The effect of NaDDTC comes from Chemisorption between Copper and Sulfur of NaDDTC. As a result, test results showed that sulfur is helpful to protect a corrosion of seawater line.