DIRECT SIMULATION AND LARGE EDDY SIMULATION OF UNSTEADY FLOW INCLUDING SEPERATION,VORTEX MOTION AND TURBULENCE

分离、涡运动和湍流非定常流动的直接模拟和大涡模拟

• 批准号: 07044323
• 负责人: KOBAYASHI Toshio
• 金额: --
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for International Scientific Research.
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044323/
• 关键词: Computational fluid dynamics; Turbulent flow; Direct numerical simulation; Large eddy simulation; HIgh order accurate scheme; Vortex; Flow separation

A purpose of this co-labolation research was to establish an accurate and effective method for the numerical simultion of unsteady flows with seperation and vortexes, esppecially using a direct numerical simulation (DNS) and a large eddy simulation (LES) of turbulence. For this purpose high-order accuracy schemes and boundary conditions were developed in the mathematical view and LES turbulence models were also examined from an physical analysis of turbulence structures.The above reseach had been performed in numerical methods of the compressible flow, high order accurate schemes and their application to the direct turbulence simulation by Chinese researchers, and also in numerical methods of the incompressible flows, boundary condition and their application to the large eddy simulation by Japanese researchers. This co-laboration promoted a development of more accurate and effective research in turbulence phenomena by an interaction between the both sides.The unsteady flows with the se … More perations and votexes are popular in the engineering, but have not been predicted correctly enough by a widely used Reynolds averaging model. The LES is expected to be applied generally and accurately to verious types of flows because it simulates a large scale part of turbulence motion directily. However, several problems should be researched before it is applied to the engineering : in mathematical view, 1) effective algorithms for the time marching analysis, 2) reducing numerical errors caused from the boundary conditions, 3) avoiding instability in the high order accuracy schemes, 4) boundary fitting method to the comlicated geometry, and also in the physical analysis, 5) development and validation of the LES turbulence models, 6) analysis of turbulence structures by the visualized data. Finally a large scale computation for the LES and DNS can be performed accurately and effectively enough.In 1995 budget year these researches were proceeded as fillows :Chinese researches investigated ina) development of stable and high order schemes with compact formulation,b) direct numarical simulation of the compressible turbulent shear flow. Japanese researchers investigated inc) instability and accuracy of the unsteady boundary conditions,d) development of dynamic models for the LES,e) large eddy simulations using the boundary fitted and unstructured grids, and also joint researches are performed inf) analysis of the visualization of the compressible shear flows by the DNS.g) applying the high order schemes to the incompressible flow simulations.This co-laboration has been proceeded by exchanging information constantly through an internet and also by visiting each other for discussing more detail. A part of this co-laboration results has been presented in an international symposium and will be published in an international journal coauthorized by the researchers from both Chinese and japanese side. This research program will be continued and extended to wider application of the DNS and LES to both the compressible and the incompressible turbulent flows. Less

合作研究的目的是建立一种准确有效的方法来模拟有分离和旋涡的非定常流动，特别是采用湍流的直接数值模拟和大涡模拟。为此，从数学的角度出发，发展了高精度格式和边界条件，并从湍流结构的物理分析出发，研究了大涡模拟中的大涡模型。中国学者在可压缩流动的数值方法、高精度格式及其在直接湍流模拟中的应用，以及日本研究人员在不可压缩流动、边界条件的数值方法及其在大涡模拟中的应用方面进行了上述研究。这种合作通过双方的相互作用促进了对湍流现象更准确和更有效的研究的发展。带有Se…的非定常流动更多的波动和涡旋在工程中很流行，但广泛使用的雷诺平均模型并不能足够准确地预测它们。由于大涡模拟直接模拟了大尺度部分的湍流运动，有望广泛而准确地应用于各种类型的流动。然而，在工程应用之前，还需要研究几个问题：1)时间推进分析的有效算法；2)减少边界条件引起的数值误差；3)避免高精度格式的不稳定性；4)复杂几何形状的边界拟合方法；5)LES湍流模型的建立和验证；6)可视化数据分析湍流结构。在1995财政年度，中国的研究主要集中在以下几个方面：(1)发展了格式紧凑的稳定高阶格式；(2)直接数值模拟了可压缩湍流剪切流。日本研究人员研究了非定常边界条件的不稳定性和精度，d)大涡动力学模式的发展，e)使用边界拟合和非结构网格进行大涡模拟，以及联合研究在分析DNS.g)可压缩剪切流可视化方面的应用。g)将高精度格式应用于不可压缩流动模拟。这种合作是通过互联网不断交换信息和相互访问以讨论更多细节来进行的。这一合作成果的一部分已在国际研讨会上发表，并将发表在由中日双方研究人员共同授权的国际期刊上。这一研究计划将继续下去，并将其推广到更广泛的应用，包括可压缩湍流和不可压缩湍流。较少

项目成果

M.Oshima: "Computational visualization of magnetic field effects on flow and temperature fields in a silicon melt flow" ASME FED 218. 1-6 (1995)

M.Oshima：“硅熔体流动中磁场对流动和温度场影响的计算可视化”ASME FED 218. 1-6 (1995)

Y.Ma: "Super compact schemes with uniform and non-uniform grid system" Proc.ISCFD. (1995)

Y.Ma：“具有均匀和非均匀网格系统的超紧凑方案”Proc.ISCFD。

M.Tsubokura: "Large eddy simulation of turbulent channel flow using an unstructured mesh" ASME FED 215. 81-87 (1995)

M.Tsubokura：“使用非结构化网格对湍流通道流进行大涡模拟”ASME FED 215. 81-87 (1995)

D.Fu: "High order accurate schemes and numerical simulation of compressible mixing layrs" Proc.ISCFD. (1995)

D.Fu：“可压缩混合层的高阶精确方案和数值模拟”Proc.ISCFD。

D.Fu: "Numerical simulation of coherent structure of 2-D compressible mixing layers" Science in Chaina Ser.A. 39 (to appear). (1996)

D.Fu：“二维可压缩混合层相干结构的数值模拟” Science in Chaina Ser.A.