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EDISON_CFD : 웹 기반의 유체공학 교육 및 연구 환경
최요한(Y. Choe),이성욱(S. Lee),김종암(C. Kim) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.5
EDISON_CFD, an abbreviation of EDucation-research Integration through Simulation On the Net for Computational Fluid Dynamics, is a web-based environment designed to support education and research for the fluid engineering. Its goal is the construction of a virtuous cycle between education and research by utilization of computational techniques. EDISON_CFD provides various simulation programs and contents for almost fluid engineering problems. Since 2011, EDISON_CFD have been used in various undergraduate courses at several universities. In this paper, we introduce the EDISON_CFD, the simulation programs and contents, and the utilization in education.
G. Kim(김광현),Y. Choe(최요한),C. Kim(김종암) 한국전산유체공학회 2016 한국전산유체공학회지 Vol.21 No.1
The present paper deals with accuracy improvement of a bleed boundary condition model used to improve the performance of supersonic inlets. In order to accurately predict the amount of bleed mass flow rates, this study performs a scaling of sonic flow coefficient data for 90-degree bleed holes in consideration of Prandtl-Meyer expansion theory. Furthermore, it is assumed that porosity varies with stream-wise location of the porous bleed plate to accurately predict downstream boundary layer profiles. The bleed boundary condition model is demonstrated through Computational Fluid Dynamics(CFD) simulations of bleed flows on a flat plate with/without an oblique shock. As a result, the bleed model shows the improved accuracy of bleed mass rates and downstream boundary layer profiles.
다양한 출구조건이 적용된 초음속 흡입구 공력불안정성 수치적 연구
홍우람(W. Hong),최요한(Y. Choe),김종암(C. Kim) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.5
The present study numerically investigates the flow instability around supersonic inlet, called inlet buzz. Though the flow conditions change linearly, behavior of inlet buzz alters hysteretically. In order to simulate the inlet buzz hysteretic character, computations are conducted with varying mass flow rate. The mass flow rate condition is controlled by an exit throttling plug which moves back and forth to change an exit area. In this paper, a set of simulations with mass flow rate control are presented. This simulations focus on hysteretic buzz characteristics of supersonic inlet according to mass flow rate and the historic path of the mass flow rate change. Firstly, an inlet buzz case with decreasing mass flow rate is simulated. In this process, the inlet buzz characteristic changes from the first mode of a low frequency regime to the second mode of a high frequency regime. In the next, the effect of the increasing mass flow rate on the inlet buzz is examined. This case shows another kind of the buzz transition that the buzz frequency becomes higher in the third mode. The hysteretic inlet buzz has many similarities to the fundamentals of a pipe-type musical instrument such as self-excited feed-back mechanism and overblowing. Considering the similarities, the hysteretic characteristics of an inlet buzz is discussed in the instrumental acoustic point of view.