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Title: 植生開水路流れの自由水面ガス輸送現象における界面流速発散モデルの開発
Other Titles: DEVELOPMENT OF SURFACE VELOCITY DIVERGENCE MODEL FOR GAS TRANSFER IN VEGETATED OPEN-CHANNEL FLOWS
Authors: 山上, 路生  kyouindb  KAKEN_id  orcid https://orcid.org/0000-0002-8146-9788 (unconfirmed)
岡本, 隆明  KAKEN_name
禰津, 家久  KAKEN_name
村田, 祐樹  KAKEN_name
Author's alias: SANJOU, Michio
OKAMOTO, Takaaki
NEZU, Iehisa
MURATA, Yuki
Keywords: gas transfer beneath freesurface
openchannel flow
vegetation
surface velocity divergence and PIV measurements
Issue Date: 2012
Publisher: 公益社団法人 土木学会
Journal title: 土木学会論文集B1(水工学)
Volume: 68
Issue: 3
Start page: 148
End page: 158
Abstract: 開水路乱流の自由水面ガス交換に焦点をあてて, 滑面と剛体植生粗度の二つの底面境界を用意し, 室内実験水路にて乱流計測および溶存酸素の計測を行った. 同じ流量および水深の場合, 滑面よりも植生流れの方が大規模な混合渦の生成によって界面流速発散強度が増加するためガス輸送が促進され, さらにガス輸送速度と植生密度には重要な関係が存在することが示された. ガス輸送速度は界面流速発散値に大きく依存することが確認できたが, 界面流速発散モデル(SDモデル)では水深の影響を考慮できないため開水路流れのガス輸送をモデル化するには不十分である. そこでSDモデルにガス輸送現象の支配因子と考えられる界面乱れエネルギーと水深スケールを組み込み, 滑面流れと剛体の水没植生流れの双方にも適用できる一般性の高い修正SDモデルを開発した.
Turbulence and DO measurements were conducted in laboratory flume, in which two kinds of bed conditions were chosen, i.e., smooth and vegetation roughness conditions. It was found that the vegetation promotes the gas transfer beneath air/water interface, because a larger surface velocity divergence is induced by a large-scale shear vortex formed in the vegetation edge. Further, we revealed a great dependency of the gas transfer on the vegetation density. Based on the measured results, a new surface divergence model was developed which can predict successfully the gas transfer velocity in the openchannel flows for the both of the smooth and vegetated bed conditions.
Rights: © 2012公益社団法人 土木学会
URI: http://hdl.handle.net/2433/194043
DOI(Published Version): 10.2208/jscejhe.68.148
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