ANALYSYS OF STRUCTURE.MODELLING AND CONTROL IN A WALL TURBULENCE BY USING LES AND DNS

使用 LES 和 DNS 进行壁面湍流结构分析、建模和控制

基本信息

批准号：
04452141
负责人：
MIYAKE Yutaka
金额：
$ 4.48万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452141/
关键词：
DNS LES WALL TURBULENCE TURBULENCE MODEL TURBULENCE CONTROL INHOMOGENEOUS TURBULENCE SPECTRAL METHOD WAVY CHANNEL FLOW 縦渦円形噴流高次精度差分乱れ構造解析

项目摘要

Discussions are presented concering the generation of streaks and fields around them in the wall turbulence using an instaneneoius LES data-base by means of a three dimensional computer graphics.As a result, it is observed that the phenomena of prpduction, diffusion, redistoribution of Reynolds shear stress appear intermittently in space around streaks, and that Reynolds shear stress is found at places where production and events of turbulence at near wall region produce negative diffusion. Also in the modelling view points, it is shown that velocity-pressure gradient term should not be splitted into pressure diffusion term and pressure-strain one. Furthermore as for regeneration process at near wall region, it is found that quasistreamwise vortices generate new vortices upwardstream of themselves. These vortices are counter-rotating and constitute a sort of chain structure. Regeneration is due to tilting of wall normal vortices and to stretching of itself.To be confirm the generality … More of turbulence structure, it is needed to investigate inhomogeneous flow. Then, we measured a flow in a wavy channel flow, namely channel having a flat plate wall on one side and wavy in the other side. Experimented data, i.e., turbulence intencity, turbulence stresses and skeweness, shows the effect of pressure gradient in the flow field.DNS code was manufactured for a round jet. As initial conditions nearly axi-symmetric or herical petrubation were assumed and calculations of temporally developing process of turbulent flow were conducted. As a result, in the case of helical peturbation, structure begins to appear earlier and maintains longer-lived coherent structure than in the nearly axi-symmetric peturabation case. It was demonstorated numerically the possibility of turbulence control and aeroacoustics control of jets.The scheme of analysys of sound source distribution and the possibilty of high resolution analysys of sound souce were also presented by using DNS.It is demonstrated that estimation of the sound source on the surface of a square cylinder by observing the large-scale structure of flow should be careful. Less

利用三维计算机图形学的瞬时 LES 数据库，讨论了壁湍流中条纹及其周围场的产生。结果，观察到雷诺兹的产生、扩散、再分布现象剪切应力间歇性地出现在条纹周围的空间中，并且在近壁区域的湍流产生和事件产生负扩散的地方也发现了雷诺剪切应力。点，表明速度-压力梯度项不应分解为压力扩散项和压力-应变项。此外，对于近壁区域的再生过程，发现准流向涡流在其自身上游产生新的涡流。反向旋转并构成一种链结构，再生是由于壁法向涡流的倾斜和自身的拉伸。为了证实湍流结构的普遍性，它是然后，我们测量了波状通道流中的流动，即一侧具有平板壁而另一侧具有波状的通道的实验数据，即湍流强度、湍流应力和偏斜度。考虑了流场中压力梯度的影响。DNS 代码是为圆形射流制作的，假设初始条件接近轴对称或螺旋磨损，并计算了时间发展过程。结果，在螺旋扰动的情况下，结构比近轴对称扰动的情况开始出现得更早，并保持更长寿命的相干结构，这在数值上证明了湍流控制和气动声学控制的可能性。还提出了声源分布分析方案以及声源高分辨率分析的可能性DNS. 证明通过观察大尺度流动结构来估计方圆柱体表面上的声源应谨慎。