Development of Accurate Numerical Methods for Turbulent Open Channel Flows with Complex Geometries

复杂几何形状的湍流明渠流精确数值方法的开发

• 批准号: 03650416
• 负责人: KAWAHARA Yoshihisa
• 金额: $ 1.22万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03650416/
• 关键词: Algebraic stress model; Open channel flows; Boundary-fitted coordinates; Convection-diffusion equation; Limiter; QUICKEST scheme; Iterative method for linear systems; Vectorization; 第2種2次流; 複断面流れ; 移流ー拡散方程式; リミター; 有限体積法; 高精度移流スキ-ム; 非線形kーεモデル

The present study is concerned with the development of numerical methods for flow calculation in River Engineering. Main achievements consist of refining a turbulence model, improving convection schemes, reformulation of basic equations on boundary-fitted coordinate systems and vectorization of computer codes for the reduction of computational time.A new algebraic stress turbulence model was proposed for turbulence-driven secondary flows. The turbulence model keeps the similar structure as the non-linear kappa - epsilon models, but has difference in variable model coefficients which enable the model independent of complex boundary geometries. Comparisons with the experimental data available for compound channel flows showed good agreement as for mean velocities and the Reynolds stresses. Models for the effect of free surface were summarized and the limiting behaviors of turbulence quantities near free surface were also discussed.Usage of boundary fitted coordinates produces new advecti … More on terms in basic equations which have non-conservative forms. This results in the sensitiveness of numerical results to the grid system employed. Combination of two coordinate systems, one for geometry, the other for velocity field was adopted to meet the problem. A regular grid system with a damping technique for pressure oscillation was used. Based on these ideas two computer codes were developed to validate the expected feature.Highly accurate and bounded scheme was proposed for convection process. A limiter was introduced to control the convection flux at the control volume face to suppress the physically meaningless oscillations.The limiter coupled with the QUICKEST scheme showed superior performance to those used so far for both linear and non-linear flow cases.Performance of many iterative solvers for linear systems were compared in terms of computational time to find out that Modified Strongly Implicit Procedure and Conjugate Gradient-like solvers are suitable for flow calculations. Techniques to vectorize many iterative solvers were devised and tested on supercomputers. Less

本研究是关于河流工程中水流计算的数值方法的发展。主要成果包括：改进了湍流模型，改进了对流格式，在边界拟合坐标系下对基本方程进行了重新表述，并对计算程序进行了矢量化以减少计算时间。湍流模型保持了非线性kappa -ε模型的相似结构，但在变模型系数上有所不同，使模型不依赖于复杂的边界条件。与复合通道流动的实验数据的比较显示出良好的协议，平均速度和雷诺应力。本文总结了自由表面效应的模型，讨论了自由表面附近湍流量的极限行为，采用边界拟合坐标产生了新的平流，并对自由表面附近湍流量的极限行为进行了分析 ...更多信息 基本方程中的非保守形式的项。这导致数值结果对网格系统的敏感性。采用几何坐标系和速度场坐标系相结合的方法来解决这一问题。使用了一个规则的网格系统与阻尼技术的压力振荡。在此基础上，编制了两个程序，验证了所期望的特征，并提出了对流过程的高精度有界格式。在控制体表面引入一个限制器来控制对流通量，以抑制无物理意义的振荡。与QUICKEST格式耦合的限制器在线性和非线性流动情况下都表现出上级目前使用的那些方法的性能。从计算时间方面比较了许多线性系统的迭代求解器的性能，发现修正强隐式方法和共轭梯度方法在计算时间上优于QUICKEST方法。类似的求解器适用于流量计算。许多迭代求解器的矢量化技术被设计出来，并在超级计算机上进行了测试。少

项目成果

Botev,I., Tamai, N. and Kawahara, Y.: "2-D sediment transport simulation in natural streams" Proc. Hydraulic Engineering, JSCE. Vol.36. 87-92 (1992)

Botev,I.、Tamai, N. 和 Kawahara, Y.：“自然河流中的二维沉积物输送模拟”Proc。

Jalil,M.A.,Kawahara,Y.and Tamai,N.: "Performance of universal limiter for QUICKEST scheme" Proc. 6th Japanese Symp. on CFD. 487-490 (1992)

Jalil，M.A.，Kawahara，Y. 和 Tamai，N.：“QUICKEST 方案通用限制器的性能”Proc。

Kawahara,Y.: "Prediction of turbulent flow in prismatic ducts with complex cross-section" J. Comput. Fluid Dynamics.

Kawahara,Y.：“具有复杂横截面的棱柱形管道中湍流的预测”J. Comput。

河原 能久: "複雑な横断面形状を有する直線管内乱流の数値解析" 第5回数値流体解析シンポジウム講演論文集. 347-350 (1991)

Yoshihisa Kawahara：“具有复杂横截面形状的直管中湍流的数值分析”第五届计算流体分析研讨会论文集347-350（1991）。

河原 能久: "流体解析における連立一次方程式の反復解法のベクトル化" 日本応用数理学会論文誌. 1. 249-261 (1991)

Yoshihisa Kawahara：“流体分析中联立线性方程迭代解的矢量化”日本应用数学学会汇刊1. 249-261 (1991)。