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오픈소스(OpenFOAM)에 기반한 내재적 방법의 압축성 전산유체해석 프로그램(ISAAC)의 개발
신훈범,정성기,김지홍,길재흥,김병윤,김정현,김규홍 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11
일반 산업체의 CFD 엔지니어들의 경우 복잡한 형상을 짧은 시간 내에 해석을 완료할 수 있는 상용프로그램에 대한 의존도가 높은 현실이다. 상용프로그램의 경우 안정성, 높은 병렬성능 및 사용자 편의성등과 같은 이점도 많지만 신속한 해석을 위해서는 많은 비용증가의 문제가 발생하게 된다. 그리고 범용성 및 폐쇄성을 특징으로 하는 상용 프로그램은 사용자 환경에 맞는 맞춤형 개발에 일부 한계를 가지게 된다. 본 연구는 비용 한계를 극복하고 사용자에 맞는 CFD 기반 프로그램을 개발하는데 일차적인 목적을 두고 수행하였으며, 짧은 개발기간 내에 최대한의 기능을 확장할 수 있는 오픈소스(OpenFOAM)를 이용하였다. 본 연구에서는 LU-SGS 수치모델을 적용한 내재적 방법의 솔버를 개발하였다. 또한, 사용자 요구도를 반영한 그래픽인터페이스(GUI), 해석업무 소요시간 단축을 위한 맞춤형 격자자동화 기능 개발, 사용자 맞춤형 후처리 기능 등을 추가적으로 개발하여 프로그램의 효율성을 제고하였다. 본 논문에서는 프로그램 개발 여러 내용 중에 수치적 내용 및 검증내용만 주요하게 소개하였다. To satisfy this needs and analyze the complex geometry problem, most of engineerings are using commercial CFD S/W which supports parallel performance, unstructured mesh, robustness and convenience. Even though the commercial CFD S/W has the several benefits, it has some problems like high costs and accessibility to optimize source code for user"s environment. So, it was needed to develop the implicit density solver CFD code based on LU-SGS scheme. Additionally, this code was developed with simple graphic user interface and several convenient function of customized automatic mesh generation and post-process interface to increase the convenience. We also validated several cases of 2D, 3D and aircraft geometry. We expect that CFD engineers can easily use the developed CFD S/W(ISAAC) and futhermore develop this program together.
신훈범,이용국,유영한,안형근,한득영,Shin, Hoon-Beom,Lee, Yong-Kuk,Yu, Young-Han,Ahn, Hyung-Keun,Han, Deuk-Young 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.12
In this paper, the equivalent circuit model of a Rosen-type multilayer piezoelectric transformer(MPT) has been proposed based on the Mason's equivalent circuit model and the principle of single layer piezoelectric plate. From the piezoelectric direct and converse effects, the symbolic expressions between the electric inputs and outputs of the MPT have been derived from the equivalent circuit model. A simplified equivalent circuit model of the MPT whose driving part has a single input form has been proposed. The symbolic expressions of the driving part have been derived from the simplified equivalent circuit model and the model was compared with the multi-input equivalent circuit model through the simulation. In the comparisons between the simulation results and the experimental data, output voltage is 630 Vp-p in case of 11-layered MPT and 670 Vp-p for 13-layered MPT over the experiment range. As the load resistance increases, output voltage increases and saturates over $300k{\Omega}$ and the resonant frequency changes from 102 kHz to 103 kHz. The simulation and the experimental results agree well over different load resistances and frequencies.
신훈범,안형근,한득영,Shin, Hoon-Beom,Ahn, Hyung-Keun,Han, Deuk-Young 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.9
This paper explains the design and fabrication of an inverter for LCD backlight using a multilayer piezoelectric transformer. That inverter is operated by the burst dimming method whose dimming signal is controlled by the duty ratio of rectangular switching signal to a PWM controller. The brightness of CCFL's are investigated according to the various dimming signals, and when those CCFL's are turned on, the temperature distributions on the piezoelectric transformer and circuit components of the inverter are also investigated by a thermo-camera.
신훈범(H.B. Shin),최원(W. Choi),서석주(S.J. Seo),유진복(J.B. Ryu) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4
Ice accretion is one of the potential hazards in airplane flight, adversely affecting aircraft aerodynamic. There are two distinct icing analysis that can be simulated. One is predicting the effect of ice on the aerodynamic performance of airfoils when ice geometry is known. The other is simulating ice accretion. This work presents the method of icing accretion analysis. This work presents an Eulerian approach to calculate the droplet collection efficiency on the 2D airfoil. The initial flow solution are obtained the FLUENT and copled with droplet motion in the ambient condition.