• Title/Summary/Keyword: Cavity Flow

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The Study on Cavity Flow in Supersonic flow field (초음속 유동장에 놓인 공동 유동에 대한 연구)

  • Yoon Y. H.;Hong S. K.;Kwon K. B.
    • 한국전산유체공학회:학술대회논문집
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    • pp.139-143
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    • 2003
  • In this study the numerical analyses on cavity flow in supersonic flow field are conducted. According to the length-to-depth ratio of cavity, the shear layer is changed, consequently influencing on vortex structure inside the cavity. Especially in case the fluid flow outside cavity impinges inside the cavity, the oscillation of the cavity flow is identified. Another result is that though the cavity flow shows the unsteadiness, characteristics of cavity flow can be represented by pressure coefficients converged.

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Control of the Pressure Oscillation in a Supersonic Cavity Flow Using a Sub-cavity (Sub-cavity를 이용한 초음속 공동유동의 압력진동 제어)

  • Lee Young-Ki;Jung Sung-Jae;Kim Heuy-Dong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.310-313
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    • 2006
  • The present study aims at investigating the effectiveness of a new passive cavity flow control technique, sub-cavity. The characteristics of cavity flow oscillation with the device are compared with those with other control techniques tested previously, including a triangular bump and blowing jet. In the computation, the three-dimensional, unsteady Navier-Stokes equations governing the supersonic cavity flow are solved based on an implicit finite volume scheme spatially and multi-stage Runge-Kutta scheme temporally. Large eddy simulation (LES) is carried out to properly predict the turbulent features of cavity flow. The present results show that the pressure oscillation near the downstream edge dominates overall time-dependent cavity pressure variations, and the amplitude of the pressure oscillation can be reduced in the presence of a sub-cavity.

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NUMERICAL ANALYSIS OF THREE DIMENSIONAL SUPERSONIC CAVITY FLOW FOR THE VARIATION OF CAVITY SPANWISE RATIO (3차원 공동의 폭변화에 따른 초음속 유동에 대한 수치분석연구)

  • Woo, C.H.;Kim, J.S.;Choi, H.I.
    • 한국전산유체공학회:학술대회논문집
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    • pp.181-184
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    • 2006
  • High-speed flight vehicle have various cavities. The supersonic cavity flow is complicated due to vortices, flow separation and reattachment, shock and expansion waves. The general cavity flow phenomena include the formation and dissipation of vortices, which induce oscillation and noise. The oscillation and noise greatly affect flow control, chemical reaction, and heat transfer processes. The supersonic cavity' flow with high Reynolds number is characterized by the pressure oscillation due to turbulent shear layer, cavity geometry, and resonance phenomenon based on external flow conditions, The resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. In the present study, we performed numerical analysis of cavities by applying the unsteady, compressible three dimensional Reynolds-Averaged Navier-Stokes(RANS) equations with the ${\kappa}-{\omega}$ turbulence model. The cavity model used for numerical calculation had a depth(D) of 15mm cavity aspect ratio(L/D) of 3, width to spanwise ratio(W/D) of 1.0 to 5.0. Based on the PSD(Power Spectral Density) and CSD(Cross Spectral Density) analysis of the pressure variation, the dominant frequency was analyized and compared with the results of Rossiter's Eq.

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NUMERICAL ANALYSIS OF THREE DIMENSIONAL SUPERSONIC CAVITY FLOW FOR THE VARIATION OF CAVITY SPANWISE RATIO (공동의 폭 변화에 따른 3차원 초음속 공동 유동연구)

  • Woo, C.H.;Kim, J.S.
    • Journal of computational fluids engineering
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    • v.11 no.4
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    • pp.62-66
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    • 2006
  • High-speed flight vehicle have various cavities. The supersonic cavity flow is complicated due to vortices, flow separation, reattachment, shock waves and expansion waves. The general cavity flow phenomena includes the formation and dissipation of vortices, which induce oscillation and noise. The oscillation and noise greatly affect flow control, chemical reaction, and heat transfer processes. The supersonic cavity flow with high Reynolds number is characterized by the pressure oscillation due to turbulent shear layer, cavity geometry, and resonance phenomenon based on external flow conditions. The resonance phenomena can damage the structures around the cavity and negatively affect aerodynamic performance and stability. In the present study, we performed numerical analysis of cavities by applying the unsteady, compressible three dimensional Reynolds-Averaged Navier-Stokes(RANS) equations with the ${\kappa}-{\omega}$ turbulence model. The cavity model used for numerical calculation had a depth(D) of 15mm cavity aspect ratio (L/D) of 3, width to spanwise ratio(W/D) of 1.0 to 5.0. Based on the PSD(Power Spectral Density) and CSD(Cross Spectral Density) analysis of the pressure variation, the dominant frequency was analyzed and compared with the results of Rossiter's Eq.

Calculation of Cavity Flow with FEM & Finite Spectral Method

  • Wang Jian-Ping;Li Ting-Wen
    • 한국전산유체공학회:학술대회논문집
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    • pp.131-133
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    • 2003
  • The streamfunction-vorticity equations for two-dimentional cavity flow are solved by a new finite element method which uses finite spectral basis functions as interpolation functions for rectangular elements. Results for several cases with different Renold's number are compared with benchmark solutions and found to be in well agreement.

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Experimental/Computational Study on the Supersonic Cavity Flow with a Sub-Cavity to Reduce the Pressure Oscillation (압력진동을 저감하기 위한 sub-cavity를 가진 초음속 공동유동에 대한 실험 및 수치해석적 연구)

  • Lim, Chae-Min;Lee, Young-Ki;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • pp.3009-3014
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    • 2007
  • The effectiveness of passive control techniques for alleviating the pressure oscillation generated in a supersonic cavity flow was investigated numerically and experimentally, respectively. The control device includes a sub-cavity installed near the leading edge of a rectangular cavity. Time-dependent supersonic cavity flow characteristics with turbulent features were examined by using the three-dimensional, mass-averaged Navier-Stokes computation based on a finite volume scheme and large eddy simulation. The results show that the pressure oscillation near the trailing edge dominates overall time-dependent cavity pressure variations. Such an oscillation can be attenuated more significantly in the presence of the sub-cavity compared with the cavity without sub-cavity, and a larger sub-cavity leads to better control performance.

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Analysis of Three-dimensional Cavity flow by using Unstructred grid (비정규 격자를 이용한 3차원 Cavity 유동 해석)

  • Kang, Hyo-Kil;Kim, Moon-Chan;Chun, Ho-Hwan
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • pp.192-197
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    • 2003
  • Three-dimensional cavity flow is analyzed with the code by using unstructured grid. Incompressible Navier-Stokes equations are used as governing equations, and governing equations are discretized by Finite Volume Method. Artificial compressibility method, proposed by Chorin, and developed by Soh, is used for coupling a pressure and a velocity. Cell-centered scheme is adopted in the code, this has the effect of having denser grid than nodal scheme when the same grid is used. Weighted Averaging scheme is used for the value at a nodal point. Cavity flow is analyzed, and this computed results are compared with the results in the research report

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Hybrid RANS/LES Simulation of Subsonic Cavity Flow (Hybrid RANS/LES 방법을 이용한 이음속 공동 유동의 수치적 모사)

  • Chang K. S.;Park S. O.;Choi S. K.
    • Journal of computational fluids engineering
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    • v.9 no.2
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    • pp.23-29
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    • 2004
  • A numerical simulation of an incompressible cavity flow is conducted using the hybrid turbulence model. The model adopted is a modified type of DES using k- ε two-equation model. Cavity geometry and flow condition are based on Cattafesta's experiment. Computational results are compared with the results of Cattafesta's experiment. The simulation successfully predicts the oscillatory features and the Strouhal number of the oscillation compares very favorably with that of the dominant mode of experimental data. Vorticity contours obtained from the simulation data are consistent with the smoke visualization of the Cattafesta's experiment. The coherent structures of cavity flow are also investigated using Q criterion.