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측류유동을 고려한 실린더 주위의 캐비테이션 유동 현상 해석
이병우(B.W. Lee),박수일(S.I. Park),박원규(W.G. Park),이건철(K.C. Lee) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.11
Cavitating flow simulation is of practical importance for many engineering systems, such as marine propellers, pump impellers, nozzles, injectors, torpedoes, etc. The present work has focused on the simulation of cavitating flow past cylinders with strong side flows. The governing equation is the Navier-Stokes equation based on the homogeneous mixture model. The momentum and energy equation is in the mixture phase while the continuity equation is solved liquid and vapor phase, separately. An implicit dual time and preconditioning method are employed for computational analysis. For the code validation, the results from the present solver have been compared with experiments and other numerical results. A fairly good agreement with the experimental data and other numerical results have been obtained. After the code validation, the strong side flow was applied to include the wake flow effects of the submarine or ocean tide.
Fractional Step Method을 이용한 원형 실린더 주위의 난류 유동해석
박금성(K.S. Park),박원규(W.G. Park) 한국전산유체공학회 2003 한국전산유체공학회 학술대회논문집 Vol.2003 No.-
As computer capacity has been progressed continuously, the studies of the flow characteristics have been performing by the numerical methods actively. Recent numerical simulation has a tendency to require the higher-order accuracy in time, as well as in space. This tendency is more true in LES and acoustic noise simulation. In this study, 3-dimensional unsteady incompressible Navier-Stokes equation was solved by numerical method using the fractional step method with the fourth order compact pade scheme to achieve high accuracy. To validate the present code and algorithm, 3D flow-field around a cylinder was simulated. The drag coefficient and lift coefficient were computed and, then, compared with experiment. The present code will be tailored to LES simulation for more accurate turbulent flow analysis.
박형 휴대폰 케이스용 고분자 재료 및 사출 조건에 관한 연구
김신우(S. -W. Kim),허윤(Y. Heo),하영욱(Y. -W. HA),박원규(W. -K. Park) 한국생산제조학회 2007 한국공작기계학회 춘계학술대회논문집 Vol.2007 No.-
This paper presents about effects that molding operational conditions affect to injection molded parts. We studied in the two aspects of the resins and mold condition for the case of slim cell phone. First of all, we choose the optimized resins through a comparative study of each resin in the condition of the regular mold processing and design. PC (Polycarbonate) is better at parts applied fatigue load and PPA (Polyphthalamide) is better at parts required strength. Mold temperature is better at over 100℃ to the strength and surface quality.
조장근(J.K. Cho),오상욱(S.W. Oh),박원규(W.G. Park),오세민(S.M. Oh),이수원(S.W. Lee) 한국전산유체공학회 1996 한국전산유체공학회 학술대회논문집 Vol.1996 No.-
The jet pump is being used in many fields for several purposes because of its simple construction and easy operation. The characteristics of the geometrical variables, pressure gradient and velocity distribution of the jet pump are studied using the CFD technique. The flow calculations through a bended nozzle, a mixing chamber and a venturi are presented and phenomenological aspects are discussed. This study solve 3-D steady incompressible Navier-Stokes equations using the Iterative time marching scheme. The governing equations are differenced with 1st-order accurate backward difference scheme for the time derivatives and 3rd-order accurate QUICK scheme for the convective terms, The Mark-and-cell concept was applied efficiently to solve continuity equation. which is differenced 2nd-order accurate central differenced scheme. The 4th-order artificial damping is added to the continuity equation for numerical stability. A O-type of grid system is generated inside a nozzle and venturi of the jet pump. It has concluded that the results of present study properly agree with physical flow phenomena.