权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

The mechanisms of the heat and mass transfer in stratified sheared turbulence and its controlling method

层状剪切湍流传热传质机理及其控制方法

基本信息

批准号：
11650201
负责人：
HANAZAKI Hideshi
金额：
$ 0.64万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650201/
关键词：
stratified flow turbulence heat transfer mass transfer rapid distortion theory numerical simulation counter-gradient-flux shear flow 成層浮力シアー

项目摘要

Solutions for the stratified sheared turbulence has been obtained by the RDT (rapid distortion theory) to investigate the effects of shear, including the counter-gradient heat flux and the vertical heat transfer. By looking for the analytical short-time approximations aud the numerical evaluation of the solution at arbitrary times, it has been clarified how the spectra of the kinetic energy and the heat affect the vertical heat flux, including the phenomenon of the counter-gradient heat flux. Particular attention has been paid to the fact that there are two time scales in stratified sheared turbulence and we have shown how the two time scales determined by the shear and the buoyancy frequency affect the turbulence. Comparison with the no-shear results shows that even with shear, initial partition of the kinetic energy and the potential energy determines the subsequent partition of the energies. The overall results agreed well with the DNS for low Froude number (strongly stratified) flows. For example, many of the characteristics of stratified sheared turbulence, e.g.the 'persistent' counter-gradient flux, has been explained by this linear theory. For the passive scalar transfer in stratified sheared turbulence, we investigated how the passive scalar spectra affect the vertical transfer of them, including the counter-gradient transfer.

通过RDT（快速畸变理论）获得了分层剪切湍流的解，以研究剪切的影响，包括反梯度热通量和垂直传热。通过寻找解析的短时近似和任意时间解的数值评估，已经阐明了动能和热量的谱如何影响垂直热通量，包括反梯度热通量的现象。我们特别关注了分层剪切湍流中存在两个时间尺度的事实，并且我们已经展示了由剪切和浮力频率确定的两个时间尺度如何影响湍流。与无剪切结果的比较表明，即使有剪切，动能和势能的初始分配也决定了随后的能量分配。对于低弗劳德数（强分层）流，总体结果与 DNS 非常一致。例如，分层剪切湍流的许多特征，例如“持续”反梯度通量，已由该线性理论解释。对于分层剪切湍流中的被动标量传递，我们研究了被动标量谱如何影响它们的垂直传递，包括反梯度传递。