著者
福留 功二 飯田 雄章 長野 靖尚
出版者
社団法人 日本伝熱学会
雑誌
日本伝熱シンポジウム講演論文集 第45回日本伝熱シンポジウム
巻号頁・発行日
pp.143, 2008 (Released:2008-05-14)

ポアズイユ乱流において,レイノルズ数を減少させていくと,乱流構造が間欠的になり,摩擦の大きい乱流領域と小さい擬層流領域が現れる.この構造は熱や運動量の輸送に大きな影響を与える.しかし,その発生メカニズムや維持機構など未知な部分が多い.本研究では,ポアズイユ乱流のレイノルズ数を100から60まで段階的に低下させた.この場合に発生する間欠構造を乱流領域と擬層流領域に分割し,それぞれの領域で縦渦やストリークなどの準秩序構造について議論する.
著者
福留 功二 塚原 隆裕 守 裕也 山本 誠
出版者
一般社団法人 日本機械学会
雑誌
熱工学コンファレンス講演論文集 2020 (ISSN:2424290X)
巻号頁・発行日
pp.0142, 2020-10-09 (Released:2021-03-17)

Direct numerical simulations (DNSs) were performed to study the dissimilarity between the heat and momentum transfer of turbulent spot structures developing in a laminar plane Couette flow. The turbulent spot was generated by pair vortices, and the Reynolds and Prandtl numbers were 450 and unity, respectively. Three types of computational domains were examined to reveal the effect of the spot development on the dissimilarity. As a result, we confirmed that the effective heat transfer state is obtained for developing a turbulent spot rather than a fully developed state. It attains the maximum when the turbulent spot grows the half size of the computational domain. Moreover, much effective heat transfer state was obtained for developing in streamwise direction rather than in spanwise direction.
著者
若菜 章 花田 信章 中川 幸夫 鳥飼 芳秀 福留 功 朴 成敏
出版者
九州大学農学部附属農場
雑誌
九州大学農学部農場研究報告 (ISSN:13465643)
巻号頁・発行日
no.11, pp.27-35, 2003-03
被引用文献数
1

ブドウにおける生理障害である縮果病の発生程度とその抑制法を検討するために,露地栽培の'ネオマスカット'3樹,'マスカットべリーA'5樹,'巨峰'3樹,およびファイロンハウスで栽培している'マスカットオブアレキサンドリア'1樹を供試した.縮果病の発生率は'マスカットオブアレキサンドリア'(11.3%)で最も高く,'巨峰'(4.9%),'ネオマスカット'(1.6%),'マスカットペリーA'(0.7%)の順に低くなった.16区分した幼果表面の成長速度は果梗に最も近い区分で最も遅く,果頂部を含む区分で次に遅く,その他の区分はほぼ同程度であったが,果実の赤道から果頂側の方が果梗側より成長速度がやや速かった.H字型整枝樹における主枝の基部から先端部までの5区分間では,縮果病の発生率に有意差は認められなかった。縮果病の発生率は果房においては工部で高く,果房の粒数が少ないほど,また粒重が重いほど高かった.果粒(果実)においては赤道から果梗側へ1/2までの区分で著しく発生率が高く(約60%),果頂部では発生が認められなかった.縮果病果粒は障害程度が重いほど果重が減ったが,糖度はほとんど変化しなかった。'巨峰'の縮果病果では,着色が不良であった.第1迅速成長期の後期に0.2Mの炭酸カルシウム,硫酸カルシウム,硫酸マグネシウムおよびホウ酸の単独のあるいは混合した水溶液で'ネオマスカット'を除く3品種の果房を浸漬処理すると,いずれの処理区においても縮果病果の発生率は低くなった.しかし,'マスカットオブアレキサンドリア'におけるホウ酸水溶液の浸漬処理は効果がなかった.To demonstrate the extent of drought spot disorder in grape berries and to establish the method to depress the disorder, three trees for 'Neo Muscat', five trees for 'Muscat Bailey A', three trees for 'Kyoho', and one tree for 'Muscat of Alexandria' were chosen. The 'Muscat of Alexandria' tree was grown in a plastic house, and the other trees were grown in the open. The rate of fruits with drought spot was the highest in 'Muscat of Alexandria' (11.3 %), followed by 'Kyoho' (4.9%), 'Neo Muscat' (1.6%), and 'Muscat Bailey A' (0.7%). In young fruit surface divided transversely into 16 areas, the growth rate was the lowest in an area including the stem end, next lowest in an area including the style end, and almost same in the other areas, although it was slightly higher on the stem side half than on the style side half. There was no significant difference in the rates of berries with drought spot between five positions in the four scaffold branches trained H-shape on the horizontal trellis. In fruit clusters, the rate of fruits with drought spot was high in the shoulder Part, and increased with decrease of the number of fruits and with increase of the fruit weight. In the fruits, the rate was high (about 60%) in the areas between the equator and half position on the stem side, and no drought spot occurred in the style end area. The weight of fruit with drought spot was decreased as the extent of the disorder was high, but little was changed in the sugar content (Brix). In 'Kyoho', coloring was depressed in fruits with drought spot disorder. The immersion treatments of young clusters at the end of stage I of fruit growth in O.2M alone or combined solutions of calcium carbon dioxide, calcium sulfate, magnesium sulfate and boric acid were esulted in the reduction of the rates of fnits with disorder in three cultivars except 'Neo Muscat'. However, boric acid solution did not effect on the depression of the disorder in 'Muscat of Alexandria'.