ライブラリ登録: Guest
Turbulence Heat and Mass Transfer 5. Proceedings of the International Symposium on Turbulence Heat and Mass Transfer
September, 25-29, 2006, Dubrovnik, Croatia

DOI: 10.1615/ICHMT.2006.TurbulHeatMassTransf


ISBN Print: 978-1-56700-229-4

ISSN: 2377-2816

Analysis of Turbulent Structures of Natural Convection in a Vertical Channel by using DNS

pages 491-494
DOI: 10.1615/ICHMT.2006.TurbulHeatMassTransf.1010
Get accessGet access

要約

The objective is to clarify the mechanisms of heat transfer under the buoyancy effect. A direct numerical simulation (DNS) of natural convection in a differentially heated vertical slot is performed with the Boussinesq approximation. The discretization of computation is carried out with a spectral method for three directions. The Rayleigh number (Ra), which is defined based on an slot width and the temperature difference between both walls, is 5.4 × 105. This study also conducts a more detailed investigation on turbulence structures. The results reveals that quasi-streamwise vortices are not formed in the near-wall region and a large-scale streamwise vortical structure is dominant in the core region of the slot. We extract this large-scale structure by the proper orthogonal decomposition (POD). The energetic mode is characterized by rotational motion in which the axis is in the streamwise direction and the scale is approximately equal to the width of flow passage. Furthermore, the reconstructed flow structures with low-dimensional modes of velocity are highly correlated with those of thermal field. Therefore, these findings recommend that the streamwise-directed vortex must be controlled in order to effectively enhance the heat exchange.

Begell Digital Portal Begellデジタルライブラリー 電子書籍 ジャーナル 参考文献と会報 リサーチ集 価格及び購読のポリシー Begell House 連絡先 Language English 中文 Русский Português German French Spain