ライブラリ登録: Guest
ホーム アーカイブ Thermal Letter 役員 今後の会合 国際伝熱会議の集会
International Heat Transfer Conference 6

ISSN: 2377-424X (online)
ISSN: 2377-4371 (flashdrive)

BUOYANCY EFFECT ON EDDY DIFFUSIVITIES IN THERMALLY STRATIFIED FLOW IN AN OPEN CHANNEL

Tokuro Mizushina
Department of Chemical Engineering, Kyoto University Kyoto 606, Japan

Fumimaru Ogino
Department of Chemical Engineering, Kyoto University, Kyoto, Japan

Hiromasa Ueda
National Institute for Environmental Studies, Ibaraki, Japan

Satoru Komori
Department of Mechanical Engineering and Science Kyoto University Kyoto daigaku-Katsura, Nishikyo-ku, Kyoto, 615-8140, Japan

DOI: 10.1615/IHTC6.3110
pages 91-96

要約

This paper presents experimental results on the eddy diffusivities of momentum and heat in thermally stratified flow in an open channel under both stable and unstable conditions to provide some insight into the buoyancy effect on turbulence. The eddy diffusivities of momentum and heat were calculated as a function of position from time-smoothed velocity and temperature profiles measured by a laser Doppler velocimeter and thermocouples. The results in stable stratified flows indicate that the eddy diffusivities of momentum εm and heat εh decrease with stability and that the reciprocal turbulent Prandtl number also decreases with in¬creasing Richardson number Ri, reaching a value of about 0.1 at Ri ~ 1.
Under unstable conditions, εm and εh increase with instability and the reciprocal turbulent Prandtl number increases as the stratification shifts from neutral to weakly unstable conditions but then drops gradually as (−Ri) increases. It has a maximum of about 3 at Ri ~ −0.2 and drops to unity at Ri ~ −10. This behavior is different from other previous atmospheric measurements.

購入する $25.00 Check subscription 出版倫理および不正行為 私の図書館員へ推薦 このページをブックマークする