Wave and energy/flux oscillations in rotating stratified turbulence

旋转层状湍流中的波和能量/通量振荡

• 批准号: 13450069
• 负责人: HANAZAKI Hideshi
• 金额: $ 4.22万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450069/
• 关键词: turbulence; stratification; rotation; inertial-gravity waves; flux oscillations; rapid distortion theory

Solutions for the stratified rotating turbulence have been obtained by the RDT (rapid distortion theory) to investigate the effects of combined effects of stratification and rotation, including the counter-gradient heat flux and the vertical heat transfer. By looking for the exact analytical solutions in RDT's linear frame work, 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 rotating turbulence and we have shown how the two time scales determined by the rotation and the buoyancy frequency affect the turbulence. The overall results agreed well with the DNS for low Froude number (strongly stratified) flows. For example, many of the characteristics of stratified rotating turbulence, e.g., the phase shift of the flux oscillations due to rotation, has been explained by this linear theory. For the passive scalar transfer in stratified turbulence, we have shown the importance of the initial conditions and the unsteadiness of turbulence which have been often overlooked in the previous study of passive scalar diffusions. The results of this study will be of help in future modeling of turbulent diffusion in the atmosphere and the ocean.

RDT（快速失真理论）获得了分层旋转湍流的溶液，以研究分层和旋转效应的效果，包括反梯度热通量和垂直传热。通过寻找RDT线性框架工作中的确切分析解决方案，它已经澄清了动能和热的光谱如何影响垂直热通量，包括反梯度热通量的现象。特别注意以下事实：分层旋转的湍流中有两个时间尺度，我们已经展示了如何通过旋转和浮力频率确定的两个时间尺度影响湍流。总体结果与低弗洛德数量（强大的）流的DNS非常吻合。例如，该线性理论已经解释了分层旋转湍流的许多特征，例如，由于旋转而引起的通量振荡的相移。对于分层湍流中的被动标量转移，我们已经显示出初始条件和湍流不稳定的重要性，这些条件在先前对被动标量扩散的研究中经常被忽略。这项研究的结果将有助于将来对大气和海洋中湍流扩散的建模。

项目成果

H.Hanazaki: "Linear processes in stably and unstably stratified rotating turbulence"J.Fluid Mech.. 465. 157-190 (2002)

H.Hanazaki：“稳定和不稳定分层旋转湍流中的线性过程”J.Fluid Mech.. 465. 157-190 (2002)

H.Hanazaki: "Recirculation eddies generated by solitary waves in a rotating fluid"J.Phys.Soc.Japan. 72, in press. (2003)

H.Hanazaki：“旋转流体中孤立波产生的再循环涡流”J.Phys.Soc.Japan。

H.Hanazaki: "Linear processes in stably and unstably stratified turbulence"J. Fluid Mech.. 465. 157-190 (2002)

H.Hanazaki：“稳定和不稳定分层湍流中的线性过程”J。

H.Hanazaki: "On the behavior of wave mode and vortex mode in stratified turbulence"Transactions of JSME, Series B. 69, inpress. (2003)

H.Hanazaki：“论层状湍流中波模和涡模的行为”，JSME 汇刊，B.69 系列，印压。

余 偉明: "次世代の大気局地数値モデルの動力学的中核部分の開発"月刊「海洋」. 2月号. 107-112 (2002)

于伟明：“下一代大气局地数值模式动力核心部分的研制”，《海洋》月刊2002年107-112期。