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김영우(Y. W. Kim),박원규(W. G. Park),김찬수(C. S. Kim) 한국전산유체공학회 1998 한국전산유체공학회 학술대회논문집 Vol.1998 No.-
The numerical methodology for simulating water entry behaviors of the high-speed bodies has been developed. Since the present method assumed the impact occurs within a very short time interval, the viscous effects do not have enough time to play a significant role in the impact forces, that is, the flow around a water-entry object was assumed as an incompressible potential flow and is solved by the source panel method. The elements fully submerged into the water are routinely treated, but the elements intersected by the effective planar free surface are redefined and reorganized to be amenable to the source panel method. To validate the present code, it has been applied to the ogive model and compared with experimental data Good agreement has been obtained. The water entry behavior of the bouncing phenomena from the free surface has been also simulated using the impact forces and two degree of freedom dynamic equation. Physically, acceptable results have been obtained.
Chimera 격자 기법을 이용한 Car-like body 주위의 전체 유동 해석
오상욱(S.W. Oh),박원규(W.G. Park) 한국전산유체공학회 1997 한국전산유체공학회 학술대회논문집 Vol.1997 No.-
This paper describes analysis of complex flow around Car-like body using Chimera grid technique. As a computational algorithm, Pullboat and Chaussee's Diagonal algorithm is selected to reduce computational time. Introducing hole points flag to this Diagonal algorithm, an algorithm for Chimera grid is generated easily. This study solves 3-D unsteady incompressible Navier-Stokes equations on a non-orthogonal curvilinear coordinate system using second-oreler accurate schemes for the time derivatives, and third/second-order scheme for the spatial derivatives. The Marker-and-cell concept is applied to efficiently solve continuity equation. The fourth-order artificial damping is added to the continuity equation for numerical stability. It bas concluded that the results of present study properly agree with physical flow phenomena.
수직항력식 터빈을 이용한 풍력발전 시스템의 형상 변화 및 피치각 변화에 관한 유동해석
박찬(C. Park),박금성(G. S. Park),박원규(W. G. Park),윤순현(S. H. Yoon) 한국전산유체공학회 2004 한국전산유체공학회 학술대회논문집 Vol.2004 No.-
To analyze the performance of Wind turbine of the drag force type, 3-D RANS equations were solved by the iterative time marching method on sliding multiblock grid system. The numerical flow simulations by changing blade number and pitch angle were carried out: blade number = 15, 20 circumferentially: pitch angle = 30°, 50° radially. The torque coefficient was also calculated.<br/>
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.
Incompressible Turbulent Flow Simulation of the Rotor-Stator Configuration
김홍원(H.W. Kim),박원규(W.G. Park),정영래(Y.R. Jung),김기섭(K.S. Kim),문성균(S.G. Moon) 한국전산유체공학회 1995 한국전산유체공학회 학술대회논문집 Vol.1995 No.-
터빈익렬내부의 유동해석을 위해 비압축성 점성유동해석을 이용한 수치 해석 프로그램을 개발하였다. 지배방정식으로는 2차원의 비정상 비압축성 Navier-Stokes 방정식을 일반화된 곡선좌표계로 전환하여 암시적으로(implicitly) 반복적인 시간진행방법을 이용하여 유동해석을 하였다. 지배방정식의 각항들은 시간에 대해 1차의 정확도 그리고 영역에 대해서는 2차의 정확도, 대류항에 대해서는 3차의 정확도를 가지는 Upwind기법을 적용하였다. 특히, 실험적 접근이 매우 어려운 터빈의 정익과 회전하고 있는 동익과의 상호운동을 멀티블럭기법과 데이터 interface를 통해 보다 쉽게 해석할 수 있었다. 본 연구결과는 정익만을 계산한 타 연구자의 결과와의 비교시 매우 일치하였으며 물리적인 유동을 잘 파악 할 수 있었다. 난류유동 해석을 위해서 Baldwin-Lomax 모델을 적용하였다.
항공기 순항 상태에서의 비행 조건별 낫셀 유입 유동에 대한 전산해석
박찬욱(C.W. Park),안형진(H.J. Ahn),박원규(W.G. Park) 한국전산유체공학회 2019 한국전산유체공학회지 Vol.24 No.3
The amount of entering airflow into nacelle(engine bay) is one of important variable for determining the total amount of fire extinguish agent when the fire occurred. This study carries out 3D, steady numerical analysis of flight operating at internal and external flow field of aircraft. As a result, data of mass flow rate of entering airflow into nacelle at flight condition distinguished by altitude and Mach number was obtained. Also this study identifies the cause of unpredicted behavior of entering airflow is due to flow separation at edge of engine intake and formation of low velocity area. Effect of low velocity area was checked by Mach number distribution at end of ventilation inlet and pressure distribution at engine surface. In addition, flight conditions which the unpredicted behavior appeared were noted.