Study on the Discrete Vortex Method for Modelling Turbulent Flows

湍流模拟的离散涡法研究

基本信息

批准号：
03650142
负责人：
KAMEMOTO Kyoji
金额：
$ 1.22万
依托单位：
Yokohama National University
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-03650142/
关键词：
Vortex Model of Turbulence Discrete Vortex Method Turbulent Shear Flow Vortex Ring Interaction Vortex Element of Turbulence Large Scale Vortex Structure 三次元渦要素

项目摘要

The study on the development of the Discrete Vortex Method as a modelling of turbulence structures has been carried out, and the following results were obtained.1. Taking account of the viscous diffusion effects on its vorticity strength, the vortex model of the blob technique was modified for a simpler procedure of calculation. From a series of test calculations of interaction between two vortex rings, it was confirmed that not only the connecting proscess of the two vortex rings at an early stage of the interaction but also the splitting process at the following stage were reasonably simulated by the modified blob technique.2. The modified blob technique was applied to simulation of a flow around a sphere, and it was obtained that the boundary layer separation from the sphere surface, the formation of large scale vortex structures and the appearance of three dimensional characteristics in the wake flow were reasonably simulated as far as the starting flow calculation was concerned.3. For the estimation of pressure fluctuations, a simple method was proposed to solve the pressure Poisson equation with use of the Boundary Element Method from an instantaneous velocity field calculated by the Discrete Vortex Method, and its usefulness was confirmed from its applications for unsteady flows around a circular cylinder and a sphere.4. The modified vortex technique was applied for the more reliable simulation of flows either around a circular cylinder and various rectangular cylinders, or over a backwards-facing step, and sutisfactorily reasonable results were obtained.From the results obtained the present study, it is expected that the modified Discrete Vortex Method presented here will be applied to analyze turbulent flows in various engineering fields as one of convenient but reliable calculation methods.

已经进行了关于离散涡流方法作为湍流结构建模的研究，并获得了以下结果。1。为了考虑粘性扩散对其涡度强度的影响，对BLOB技术的涡流模型进行了修改，以进行更简单的计算过程。从两个涡流环之间的相互作用的一系列测试计算中，可以证实，不仅在交互的早期阶段连接两个涡旋环的连接，而且在下阶段的分裂过程也通过修改后的BLOB技术进行了合理的模拟。2。修改后的斑点技术用于模拟球体周围的流动，并获得了与球体表面的边界层分离，大规模涡流结构的形成以及在尾流中的三维特性的出现。为了估算压力波动，提出了一种简单的方法来通过使用离散涡流方法计算出的瞬时速度场来解决压力泊松方程，并通过其在圆形圆柱体和球体周围不稳定流动的应用中确认其有用性。4。 The modified vortex technique was applied for the more reliable simulation of flows either around a circular cylinder and various rectangular cylinders, or over a backwards-facing step, and sutisfactorily reasonable results were obtained.From the results obtained the present study, it is expected that the modified Discrete Vortex Method presented here will be applied to analyze turbulent flows in various engineering fields as one of convenient but reliable calculation 方法。