B171 鉛直円管内気泡流中の連続相の乱流構造変化 : 高時間分解能時系列 PIV による乱流微細構造の抽出

概要

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Turbulence modification in the presence of bubbles was investigated by time-series measurements using a high-time resolution PIV. The experiments were carried out in a fully-developed vertical pipe with upflow of water at the Reynolds number of 9700 and the void fraction of 0.5%. The two-dimensional flow structure in the vicinity of bubbles was measured by a high-time resolution PIV with fluorescent tracer particles and bubbles shapes and positions were obtained by using a shadow imaging technique. It is observed that turbulence production was rapidly decreased and dissipation rate was enhanced in a whole region. A strong vorticity region was generated in front of bubbles, on the other hand, vorticities behind bubbles show larger values and exist longer in center of pipe than near the wall.
社団法人日本機械学会の論文
2003-11-10