Local flow structure around bubbles under pressure-oscillating field and its application

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420107
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Fluid engineering
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Iwata Shuichi 名古屋工業大学, 工学(系)研究科(研究院), 准教授 (00293738)
• Co-Investigator(Renkei-kenkyūsha): TAKAHASHI Tsutomu 長岡技術科学大学, 機械系, 教授 (20216732)
• Research Collaborator: ONUMA Takashi 株式会社フォトロン
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 非ニュートン流 / 粘弾性流体 / 流動複屈折 / 伸張粘度

Outline of Final Research Achievements

The aim of this research it to find local flow structure around 1 micro-litter bubble(s) under pressure oscillating field. We tried measuring the retardation profile near the bubble(s) by the high speed polarization camera, as well as flow visualization experiments using tracer particles. It turns out that there is a uniaxial extension behind each bubble, and strong retardation can be seen at the region. Due to expansion and contraction of the bubbles, there are complex flow structures in the vicinity of bubbles in a viscoelastic fluid. We have studied the effect of a pressure-oscillation source position on the motion of bubbles.It turned out that an uniaxial extension was observed in the opposite side of the movement direction of the contracting bubble. It was considered that strong retardation and the motion of fine bubbles were suggested to generate negative wake. The similar flow structure was observed around a bubble in a continuous flow channel.

Free Research Field

非ニュートン流体力学