Turbulence Structure of Stable Boundary Layers with a Near-Linear Temperature Profile |
| |
| Authors: | Yuji Ohya Takanori Uchida |
| |
| Institution: | (1) Ocean-Atmosphere Dynamics Division, Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan |
| |
| Abstract: | By using a thermally stratified wind tunnel, we have successfullysimulated stably stratified boundary layers (SBL), in which the meantemperature increases upward almost linearly. We have investigated the flow structure and the effects of near-linearstable stratification on the transfer of momentum and heat. Thevertical profiles of turbulence quantities exhibit different behaviour in two distinct stability regimes of the SBLflows with weak and strong stability. For weak stability cases, theturbulent transfer of momentum and heat is basically similar to that for neutral turbulent boundary layers, although it is weakenedwith increasing stability. For strong stability cases, on the other hand,the time-mean transfer is almost zero over the whole boundary-layer depth.However, the instantaneous turbulent transfer frequently occurs in bothgradient and counter-gradient directions in the lower part of the boundary layer. This is due to the Kelvin–Helmholtz (K–H) shear instability and therolling up and breaking of K–H waves. Moreover, the internal gravity wavesare observed in the middle and upper parts of all stable boundary layers. |
| |
| Keywords: | Internal gravity wave K– H instability Stable boundary layer Temperature profile Turbulent structure Wind-tunnel experiment |
| 本文献已被 SpringerLink 等数据库收录！ |
|
