• Title/Summary/Keyword: Compressible Flow

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EFFICIENT COMPUTATION OF COMPRESSIBLE FLOW BY HIGHER-ORDER METHOD ACCELERATED USING GPU (고차 정확도 수치기법의 GPU 계산을 통한 효율적인 압축성 유동 해석)

  • Chang, T.K.;Park, J.S.;Kim, C.
    • Journal of computational fluids engineering
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    • v.19 no.3
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    • pp.52-61
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    • 2014
  • The present paper deals with the efficient computation of higher-order CFD methods for compressible flow using graphics processing units (GPU). The higher-order CFD methods, such as discontinuous Galerkin (DG) methods and correction procedure via reconstruction (CPR) methods, can realize arbitrary higher-order accuracy with compact stencil on unstructured mesh. However, they require much more computational costs compared to the widely used finite volume methods (FVM). Graphics processing unit, consisting of hundreds or thousands small cores, is apt to massive parallel computations of compressible flow based on the higher-order CFD methods and can reduce computational time greatly. Higher-order multi-dimensional limiting process (MLP) is applied for the robust control of numerical oscillations around shock discontinuity and implemented efficiently on GPU. The program is written and optimized in CUDA library offered from NVIDIA. The whole algorithms are implemented to guarantee accurate and efficient computations for parallel programming on shared-memory model of GPU. The extensive numerical experiments validates that the GPU successfully accelerates computing compressible flow using higher-order method.

Comparative study between TVD and MOC methods for the analysis of Unsteady compressible flow in pipe network (배관망의 비정상상태 압축성 유동해석을 위한 TVD 와 MOC 방법의 비교 연구)

  • Shin Young-Seob;Sah Jong-Youb
    • 한국전산유체공학회:학술대회논문집
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    • pp.101-108
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    • 2000
  • Pipe network analysis is analyze all of it about pressure and volume flow rate through that are pipeline, junction, regulator and valve etc. In this study is compare TVD with MOC method for analysis of unsteady compressible flow in pipelines. Then, we calculated unsteady compressible flow for pipe network that periodic volume flow rate conditions.

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Extension of Incompressible Flow Solver Algorithm to Analyze Compressible Flowfield (비압축성 유동해석 알고리듬 확장을 통한 압축성 유동장 해석)

  • Lim, Yeong-Taek;Kim, Moon-Sang
    • Journal of Aerospace System Engineering
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    • v.2 no.2
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    • pp.20-27
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    • 2008
  • The characteristics of compressible flow are different from those of incompressible flow from the mathematical and physical point of view. Therefore, the way to solve the flowfield is different between compressible flow and incompressible flow. In general, density-based numerical algorithm is mainly used for compressible flow solver development. On the other hand, incompressible flow solver prefers to use pressure-based numerical algorithm. In this research, a compressible Navier-Stokes flow solver is developed by means of extending from pressure-based incompressible numerical algorithm to handle both compressible and incompressible flows using the same flow solver. The present flow solver is tested at various speed ranges and compared with the solutions of density-based compressible flow solver. Numerical results show a good agreement between two flow solvers.

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Two-Dimensional Adaptive Mesh Generation Algorithm and its Application with Higher-Order Compressible Flow Solver

  • Phongthanapanich, Sutthisak;Dechaumphai, Pramote
    • Journal of Mechanical Science and Technology
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    • v.18 no.12
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    • pp.2190-2203
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    • 2004
  • A combined procedure for two-dimensional Delaunay mesh generation algorithm and an adaptive remeshing technique with higher-order compressible flow solver is presented. A pseudo-code procedure is described for the adaptive remeshing technique. The flux-difference splitting scheme with a modified multidimensional dissipation for high-speed compressible flow analysis on unstructured meshes is proposed. The scheme eliminates nonphysical flow solutions such as the spurious bump of the carbuncle phenomenon observed from the bow shock of the flow over a blunt body and the oscillation in the odd-even grid perturbation in a straight duct for the Quirk's odd-even decoupling test. The proposed scheme is further extended to achieve higher-order spatial and temporal solution accuracy. The performance of the combined procedure is evaluated on unstructured triangular meshes by solving several steady-state and transient high-speed compressible flow problems.

DEVELOPMENT OF A ROBUST MESHLESS METHOD FOR 2-D COMPRESSIBLE FLOW (2차원 압축성 유동 해석을 위한 강건한 무격자 해석기법 개발)

  • Huh, J.Y.;Rhee, J.S.;Kim, K.H.;Jung, S.Y.
    • Journal of computational fluids engineering
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    • v.19 no.3
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    • pp.85-90
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    • 2014
  • The purpose of this study is to develop a new Meshless Method to solve 2-D compressible flow problems numerically. This paper includes a revised Least Square method that improves robustness compared with its original version by removing excessive numerical oscillation which occurs when points are randomly distributed. Numerical analyses of hypersonic flow over a blunt body were carried out using the method, then robustness, accuracy and convergence of their results were compared with those obtained from the original method.

A STUDY ON EXPERIMENTAL AND NUMERICAL ANALYSIS ON THE COMPRESSIBLE FLOW INTO A BUTTERFLY VALVE (버터플라이 밸브를 통과하는 압축성 유동에 대한 실험 및 수치해석적 연구)

  • Hwang, K.S.;Chang, M.S.;Hong, J.P.;Heo, H.S.
    • 한국전산유체공학회:학술대회논문집
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    • pp.181-186
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    • 2007
  • Compressible flow characteristics in a butterfly valve is studied experimentally and numerically. The disk angle of the valve is changed as $0^{\circ}{\sim}30^{\circ}$. The SST model is used to represent the turbulent effect in the commercial code, CFX11. It was found that the numerical results are similar to the experimental ones, general discussions are given to the pressure distributions upon the disk angle of the valve.

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LARGE EDDY SIMULATION OF THE COMPRESSIBLE FLOW OVER A CAVITY WITH HIGH ASPECT RATIO

  • Oh Keon Je
    • Journal of computational fluids engineering
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    • v.9 no.1
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    • pp.1-9
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    • 2004
  • Large eddy simulation is used to investigate the compressible flow over a cavity with high aspect ratio. The sub-grid scale stresses are modeled using the dynamic model. The compressible Navier-Stokes equations are solved with the sixth order accurate compact finite difference scheme in the space and the 4th order Runge-Kutta scheme in the time. The buffer Bone techniques are used for non-reflecting boundary conditions. The results show the shear layer oscillation over the cavity. The votical disturbances, the roll-up of vorticity, and impingement and scattering of vorticity at the downstream cavity edge can be seen in the shear layer. Several peaks for the resonant frequencies are found in the spectra of the vertical velocity at the center-line. The most energetic Peak near the downstream edge is different from that at the center part of the cavity The pressure has its minimum value in the vortex core inside the cavity, and becomes very high at the downstream face of the cavity. The variation of the model coefficient predicted by the dynamic model is quite large between 0 and 0.3. The model coefficient increases in the stream-wise evolution of the shear layer and sharply decreases near the wall due to the wall effect.

LARGE EDDY SIMULATION OF THE COMPRESSIBLE FLOW OVER A OPEN CAVITY (큰에디모사기법을 이용한 공동 주위의 압축성유동 해석)

  • 오건제
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.1
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    • pp.40-48
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    • 2003
  • Large eddy simulation is used to investigate the compressible flow over a open cavity, The sub-grid scale stresses are modeled using the dynamic model. The compressible Navier-Stokes equations are solved with the sixth order accurate compact finite difference scheme in the space and the 4th order Runge-Kutta scheme in the time. The results show a typical flow pattern of the shear layer mode of oscillation over the cavity. The votical disturbances, the roll-up of vorticity, and impingement and scattering of vorticity at the downstream cavity edge can be seen in the shear layer. Predicted acoustic resonant frequency is in good agreement with that of the empirical formula. The mean flow streamlines are nearly horizontal along the mouth of the cavity. The pressure has its minimum value in the vortex core inside the cavity.