Study on the Discrete Vortex Method for Modelling Turbulent Flows

湍流模拟的离散涡法研究

• 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

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.

本文对离散涡方法作为湍流结构模型的发展进行了研究，取得了以下成果.考虑到粘性扩散对涡量强度的影响，对涡团技术的涡量模型进行了修正，使计算过程更为简单。通过对两涡环相互作用的一系列试验计算，证实了改进的blob技术不仅能合理地模拟两涡环相互作用初期的连接过程，而且能合理地模拟随后阶段的分裂过程.将改进的blob技术应用于球体绕流的数值模拟，得到了在起动流计算方面，能够合理地模拟出球体表面的边界层分离、大尺度涡结构的形成以及尾流中三维特征的出现.对于压力脉动的估计，提出了一种利用边界元法从离散涡法计算的瞬时速度场求解压力泊松方程的简单方法，并通过对圆柱和球的非定常绕流的应用验证了该方法的有效性.应用改进的涡技术对圆柱和各种矩形柱的绕流以及后台阶的绕流进行了较为可靠的模拟，得到了较为合理的结果。本文提出的修正离散涡方法，可望作为一种方便而可靠的方法，应用于各种工程领域的湍流分析计算方法

项目成果

中西 裕二: "粘性効果を考慮するための渦モデルの改良" 日本機械学会論文集(B編). 58-552. 107-112 (1992)

Yuji Nakanishi：“考虑粘性效应的涡流模型的改进”，日本机械工程师学会汇刊（编辑 B）107-112（1992 年）。

中西 裕二: "粘性効果を考慮するための渦モデルの改良" 日本機械学会論文集(B編). 58-55. 107-112 (1992)

Yuji Nakanishi：“考虑粘性效应的涡流模型的改进”，日本机械工程师学会汇刊（编辑 B）107-112（1992 年）。

Yuji Nakanishi and Kyoji Kamemoto: "Numerical Simulation of Flow around a Sphere with Vortex Blobs" Journal of Wind Engineering. 52. 267-272 (1992)

Yuji Nakanishi 和 Kyoji Kamemoto：“带有涡流的球体周围流动的数值模拟”风工程学杂志。

Y.NAKANISHI: "Numerical Simulation of Flow around a Sphere with Vortex Blobs." Journal of Wind Engineering. 52. 267-272 (1992)

Y.NAKANISHI：“带有涡流的球体周围流动的数值模拟。”

Yuji Nakanishi, Kyoji Kamemoto and Motoharu Nishio: "Modification of a Vortex Model for Consideration of Viscous Effect( An Examination of the Vortex Model on Interaction of Vortex Rings)" Transactions of JSME, B. 58-552. 107-112 (1992)

Yuji Nakanishi、Kyoji Kamemoto 和 Motoharu Nishio：“考虑粘性效应的涡模型的修改（对涡环相互作用的涡模型的检验）”JSME 交易，B. 58-552。