Control of Pressure Gradient-Driven Spatio-temporal Patterns in Strongly Correlated Soft Materials

强相关软材料中压力梯度驱动时空模式的控制

• 批准号: 13031045
• 负责人: KAWAGUCHI Masami
• 金额: $ 22.08万
• 依托单位: Mie University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13031045/
• 关键词: Hele-Shaw Cell; Correlated Soft Materials; Viscous Fingering; Saffman-Taylor Instability; Modified Darcy's Law; Bubble Motion; Strouhal Number; Karman Flow; ソフトマテリアル; 気泡; 高分子; 分岐因子; カルマン渦流れ; 乱流渦流れ; 時空間構造; エマルション; クラック状のパターン; カスプ状パターン; せん

The onset imposed shear rate 2V_f/b at which the Saffinan-Taylor instability, namely changes in the fingering pattern from the Saffinan-Taylor to the tip splitting ones occur for the first time, is in good agreement with that where the rheological properties of the displaced strongly correlated soft materials, such as polymer solutions, suspensions, and emulsions show non-Newtonian behavior irrespective of the material. The average velocity of the finger growth is almost coincident with that of the modified Darcy's law, in which the viscosity is displaced by the shear rate dependent viscosity, irrespective of the injected fluid and the Hele-Shaw cell. Therefore, the fundamental equation of viscous fingering in the soft materials can be obtained for the finger growth and it seems to be useful further to develop theoretical works and computer simulations for their viscous fingering results.The bubble motion is changed from monotonous vibration to straight paths through damped one, due to the viscoelastic properties of the HPMC layer adsorbed at the air-water interface. Below the Strouhal number of 0.2, the Karman vortex street is observed in the wake behind rising bubbles, whereas above the Strouhal number of 0.2, the wake structures are different from the Karman vortex street. The difference should be attributed to changes in flow from the Karman to turbulent flow.

萨菲南-泰勒不稳定性（即指法从萨菲南-泰勒到尖端分裂的指法第一次发生变化）的起始施加剪切速率 2V_f/b 与流变特性非常一致。置换的强相关软材料，例如聚合物溶液、悬浮液和乳液，无论材料如何，都表现出非牛顿行为。手指生长的平均速度几乎与修正的达西定律一致，其中粘度被剪切速率相关的粘度所取代，而与注入的流体和 Hele-Shaw 单元无关。因此，可以得到软材料中粘性指法的基本方程，以用于指法的生长，并且进一步发展其粘性指法结果的理论工作和计算机模拟似乎是有用的。气泡运动从单调振动变为直线运动由于 HPMC 层吸附在空气-水界面上的粘弹性，因此通过阻尼层。在斯特劳哈数低于 0.2 时，在上升气泡后面的尾流中观察到卡门涡街，而在斯特劳哈数 0.2 以上时，尾流结构与卡门涡街不同。这种差异应归因于从卡门流到湍流的流动变化。

项目成果

Viscous Fingering: "Instabilities in an Oil in Water Emulsion"Phys.Fluids. 16(in press). (2004)

粘性指法：“水包油乳液中的不稳定性”Phys.Fluids。

Masami Kawaguchi: "Viscous Fingering instabilities in an Oil in Water Emulsion"Phys.Fluids. 16・6(in press). (2004)

Masami Kawaguchi：“水包油乳液中的粘性指法不稳定性”Phys.Fluids 16・6（出版中）。

川口正美: "コロイド分散系のヴィスコスフィンガリング"高分子加工. 51・7. 298-302 (2002)

川口正美：“胶体分散体系中的粘滞指法”，聚合物加工 51・7。

Masami Kawaguchi: "Viscous Fingering in Polymeric Systems"Nonlinear Anal.. 47. 907-918 (2001)

川口正美：“聚合物系统中的粘性指法”非线性分析.. 47. 907-918 (2001)

M.Kawaguchi: "Viscous Fingering Instability in Polymer Solutions"Recent Res. Develop. Polymer Sci.. 6. 139-160 (2002)

M.Kawaguchi：“聚合物溶液中的粘性指进不稳定性”最近的研究。