| 作成者 |
|
|
|
|
|
|
|
|
|
|
|
| 本文言語 |
|
| 出版者 |
|
|
|
| 発行日 |
|
| 収録物名 |
|
| 巻 |
|
| 開始ページ |
|
| 終了ページ |
|
| 出版タイプ |
|
| アクセス権 |
|
| JaLC DOI |
|
| 概要 |
Wind tunnel simulation of the atmospheric stable boundary layers (SBL) developed over a rough surface was conducted by using a thermally stratified wind tunnel of Research Institute for Applied Mechan...ics (RIAM), Kyushu University. The present experiment is a continuation of the work carried out in a wind tunnel of Colorado State University, where the SBL flows were developed over a smooth surface. Stably stratified flows were created by heating the wind tunnel airflow to a temperature of about 40-50℃ and by cooling the test-section floor to a surface temperature of about 10 ℃. To simulate the rough surface, a chain roughness was placed over the test-section floor. We have investigated the buoyancy effect on the turbulent boundary layers developed over a rough surface for a wide range of stability, particularly focusing on the turbulence structure and transport process in the very stable boundary layers. The present experimental results broadly confirm the results obtained in the CSU experiment with smooth surface and emphasizes the following features: the vertical profiles of turbulence statistics exhibit different behavior in two distinct stability regimes of the SBL flows with weak and strong stability, corresponding to the difference in the vertical profiles of the local Richardson number. The two regimes are separated by the critical Richardson number. The magnitudes in turbulence intensities and turbulent fluxes for the weak stability regime are much greater than those of the CSU experiments because of the greater surface roughness. For the very stable boundary layers, the turbulent fluxes of momentum and heat tend to vanish and wave-like motions due to the Kelvin-Helmholtz instability and the rolling up and breaking of those waves can be observed. Furthermore, the appearance of internal gravity waves is suggested from cross-spectrum analyses.続きを見る
|
Mendeley出力
