• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.5
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• pp.101-108
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• 2002

A numerical simulation of an incompressible cavity flow is conducted. Two dimensional Navier-Stokes equations are integrated using staggered grid and a finite volume method with C-QUICK scheme for spatial derivatives and fully implicit scheme for the time derivatives. SIMPLE-C algorithm is employed to solve the pressure field. Computational results show that the third eddy is generated in the shear layer mode but not in the steady mode. This signifies that the third eddy plays an important role in cavity flow stability. As a means to control the flow, jet blowing is applied to a position below the cavity upstream edge. Effects of flow control parameters on the stability such as the frequency, the phase, and the velocity magnitude are reported.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.371-376
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• 2013

고속열차의 운행속도가 증가함에 따라 이전보다 공기역학적인 요소들의 중요성이 커지고 있다. 열차와 터널의 형상설계뿐만 아니라 주변 환경을 위해 고속 주행하는 열차 주변의 유동장을 이해할 필요성이 있다. 본 연구에서는 고속 주행으로 인해 열차 주변에 발생하는 열차풍을 분석하여 선로 주변에 작용하는 풍하중을 계산하였고, 터널 주행 시 발생하는 압력변동과 객차 연결부의 비정상 열린 공동 유동을 살펴보았다. 그 결과 2차원 해석의 정량적 한계점이 나타났지만, 정성적인 경향은 선행연구와 잘 일치함을 확인할 수 있었다. 따라서 고속열차 주변의 공기역학적 특성의 이해와 열차 및 터널의 형상 변화에 따른 상대적인 비교를 위해서는 EDISON_CFD를 이용한 2차원 해석이 유용함을 볼 수 있었다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.3
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• pp.231-236
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• 2015

Investigations into cavity flows have been conducted for decades now, most of them being about zero-pressure-gradient flows entering a cavity on a straight wall. However, the flow over curved walls in real-life situations has not been fully investigated. As cavity flows on curved walls exert centrifugal force, these walls are likely to possess different features from straight walls. To verify this possibility, this study investigated cavity flows on curved walls. Using numerical method, the effect of two variables, namely, radius of curvature on a curved wall and inlet Mach number, were investigated for subsonic and supersonic cavity flows. The result demonstrates that the value of the peak pressure generated inside the cavity increases with the decrease in the radius of curvature on a curved wall or an increase in the inlet Mach number. The total pressure loss in the cavity also results in an increase in the cavity drag.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.239-243
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• 2005

Fully three-dimensional Large Eddy Simulation calculations of the flow past 2D cavity are conducted to study the purging of neutrally buoyant or dense miscible contaminants introduced instantaneously inside the cavity. The length to depth ratio(L/D) is 2 and Reynolds number based on the depth is 3,360. Fully developed turbulent inflow are fed at the inlet from precursor simulation of channel flow. Mean flow pattern and unsteady features are investigated based on the experimental data of Pereira and Sousa. From the study of mass exchange processes, it is found that the mechanism of removal of the contaminant is very different between the non-buoyant and buoyant cases. In the buoyant case, internal wave motion which interacts with a strong cavity vortex is dominant in the ejection mechanism of the contaminants.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.477-483
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• 2015

Investigations into cavity flows have been conducted for noise and vibration problems that arise in cavity systems. Cavity systems have been applied in engineering devices and have undergone rapid development in the aerospace industry. Meanwhile, to the author's best knowledge, the cavity on a curved wall has been seldom studied. The present work is conducted to study the flow physics of a cavity mounted on a curved wall. Numerical analysis is performed to investigate the cavity flow. Two variables of sub- and supersonic cavity flows were considered: the radius of curvature of the curved wall (L/R) and the inlet Mach number. The results show that the uniform vortex generated by the cavity flow on the curved wall stabilize the pressure fluctuation as time passes. As the inlet Mach number increases, the pressure fluctuation amplitude increases. The results obtained from the curved wall are compared with those from a straight wall using Rossiter's formula. The Strouhal number of the curved wall is lower than that of the straight wall. Lower Strouhal numbers have been obtained in the present computational fluid dynamics (CFD) results than in the theoretical results using Rossiter's formula.

• Journal of computational fluids engineering
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• v.10 no.3 s.30
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• pp.48-54
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• 2005

Three-dimensional incompressible flow past an open cavity in a channel is investigated using Detached Eddy Simulation(DES). The length to depth ratio of the cavity is 2 and the Reynolds number defined with the cavity depth is 3,360. The DES methods are based on the Menter's SST model. In the present work, two types of inflow conditions are used: one is RANS profile, the other is LES inflow from another Large Eddy Simulation(LES) of fully developed channel flow. The results are compared with experimental data and LES results in terms of the mean statistics, temporal physics and scalar transport phenomenon of the flow.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.148-152
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• 2005

The three-dimensional incompressible flow past an open cavity in a channel is investigated using Detached Eddy Simulation(DES). The length to depth ratio of the cavity is 2 and the Reynolds number defined with the cavity depth is 3,360. The DES methods are based on the Mentor's SST model. In the present work, two types of inflow conditions are used; one is RANS profile, the other is LES inflow from another Large Eddy Simulation(LES) of fully developed channel flow. The results are compared with experimental data and LES results in terms of the mean statistics and temporal physics of the flow.