FUNDAMENTAL STUDY ON SIMULATION OF ATMOSPHERIC FLOW PREDICTION WITH DENSITY STRATIFICATION

密度分层大气流量预测模拟基础研究

• 批准号: 14550151
• 负责人: NISHIDA Hodetoshi
• 金额: $ 1.79万
• 依托单位: KYOTO INSTITUTE OF TECHNOLOGY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550151/
• 关键词: density stratification; atmospheric flow; pseudo-compressibility method; finite difference method; incompressible flow; 圧縮性ナビェ・ストークス方程式; 仮想境界法; デカルト格子法

In this research project, the computational codes were developed in order to simulate atmospheric flow problems with density stratification. The governing equations are the incompressible and compressible Navier-Stokes equations. The method of lines (MOL) approach is adopted in both equations. The MOL approach is constructed by the spatial discretization and time integration. In the spatial discretization, the variable order proper convective scheme and the modified differential quadrature method are used for the convection and diffusion terms, respectively. Both discretization techniques give the arbitrary order of spatial accuracy by changing only 1 parameter. And the resulting system of ordinary differential equations in time is integrated by the Runge-Kutta type scheme. In this project, the order of spatial accuracy is fixed by the second order. Also, the virtual boundary method is incorporated into the method. Usually, the flows with complicated. geometry are computed on the bound … More ary fitted coordinate (BFC) system. However, the BFC system has the lack of efficiency. Instead of the BFC, in the virtual boundary method, the computation is carried out on the Cartesian grid. Moreover, the local mesh refinement technique is used for obtaining the high resolution.The present method is applied to flows around a circular cylinder and the results are in very good agreement with other computational results. The computational time is 2/3 times the uniform Cartesian grid. Then, the flows around a sphere are simulated up to Reynolds number Re=1000. In Re=1000, the transition from laminar to turbulent flow can be reappeared. The flow around multi-spheres is simulated and the results show that the released vortices are interacted each other. Also, the flows over an isolated mountain is simulated in order to investigate the effect of density stratification. The results show clearly that the vortex structure behind of the mountain is different by the density stratification.These results are opened by the international conferences. Then, it is concluded that the present method is very promising for the environmental simulations. Less

在本研究计画中，发展了计算程式以模拟具有密度分层的大气流动问题。控制方程为不可压缩和可压缩Navier-Stokes方程。两个方程均采用直线法（MOL）。MOL方法由空间离散和时间积分构成。在空间离散中，对流项和扩散项分别采用变阶固有对流格式和修正微分求积法。这两种离散化技术仅通过改变1个参数即可给出任意阶的空间精度。并将所得的常微分方程组在时间上用龙格-库塔格式进行积分。在这个项目中，空间精度的顺序是由二阶固定的。此外，虚拟边界法被纳入到该方法。通常情况下，流程复杂。在边界上计算几何 ...更多信息 坐标系（BFC）。然而，BFC系统存在效率不足的问题。在虚边界法中，计算是在笛卡尔网格上进行的，而不是BFC。采用局部网格加密技术获得了高分辨率的数值解，并将该方法应用于圆柱绕流问题，计算结果与其它计算结果吻合较好。计算时间是均匀笛卡尔网格的2/3倍。然后，模拟了雷诺数Re=1000的球体绕流。在Re=1000时，可以再现层流到湍流的转变。对多球绕流进行了数值模拟，结果表明，释放的涡是相互作用的。此外，一个孤立的山区，以调查密度分层的影响进行了模拟。结果清楚地表明，由于密度层结的不同，山后的涡旋结构也不同，这一结果被国际会议公开。最后，本文提出的方法在环境模拟中具有很好的应用前景。少

项目成果

H.Nishida: "Comparison of a Spectral Method with a Higher-Order Finite Difference Method in Direct Numerical Simulations of Three-Dimensional Homogeneous Turbulence"Transactions of the Japan Society for Mechanical Engineers Series B. (In Japanese). 69-679

H.Nishida：“三维均匀湍流直接数值模拟中谱法与高阶有限差分法的比较”日本机械工程师学会会刊 B 系列（日语）。

H.Nishida: "Parallel DNS of Homogeneous Isotropic Turbulence Using Variable Order Method of Lines"Computational Fluid Dynamics 2002 (Springer). 305-310 (2003)

H.Nishida：“使用线的变阶方法的均质各向同性湍流的并行 DNS”计算流体动力学 2002（Springer）。

H.NISHIDA, N.SATOFUKA: "A Variable Order Method of Lines : Accuracy, Conservation and Applications"Lecture Notes in Computational Science and Engineering (Springer). 21. 167-174 (2002)

H.NISHIDA、N.SATOFUKA：“线的变阶方法：准确性、守恒和应用”计算科学与工程讲义（Springer）。

H.Nishida: "Massively Parallel DNS of Homogeneous Isotropic Turbulence"Proc. of the 5th JSME-KSME Fluid Engineering Conference. (2002)

H.Nishida：“均匀各向同性湍流的大规模并行 DNS”Proc。

H.Nishida: "A Variable Order Method of Lines : Accuracy, Conservation and Applications"Lecture Notes in Computational Science and Engineering (Springer). 21. 167-174 (2002)

H.Nishida：“线的变阶方法：准确性、守恒和应用”计算科学与工程讲义（Springer）。