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.

采用快速畸变理论（RDT）求解了旋转湍流的分层解，研究了旋转和分层的联合作用对湍流逆梯度热流和垂直换热的影响。通过在RDT的线性框架下寻找精确的解析解，阐明了动能谱和热量谱对垂直热通量的影响，包括逆梯度热通量现象。特别注意的事实是，有两个时间尺度在分层旋转湍流，我们已经表明如何由旋转和浮力频率决定的两个时间尺度影响湍流。总体结果同意与DNS低弗劳德数（强烈分层）流。例如，分层旋转湍流的许多特征，例如，由旋转引起的通量振荡的相移已经由该线性理论解释。对于分层湍流中的被动标量传输，我们指出了在以往的被动标量扩散研究中常常被忽略的初始条件和湍流的非定常性的重要性。本文的研究结果将有助于今后大气和海洋湍流扩散的模拟。

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: "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: "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: "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。

T.Miyazaki, A.Asai, M.Yamamoto, S.Fujishima: "Numerical validation of quasigeostrophic ellipsoidal vortex model"J. Phys. Soc. Japan. 71. 2687-2699 (2002)

T.Miyazaki、A.Asai、M.Yamamoto、S.Fujishima：“准地转椭球涡模型的数值验证”J。