2003 Fiscal Year Final Research Report Summary
Control of Pressure Gradient-Driven Spatio-temporal Patterns in Strongly Correlated Soft Materials
| Project/Area Number |
13031045
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Mie University |
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Principal Investigator |
KAWAGUCHI Masami KAWAGUCHI,Masami, 工学部, 教授 (30093123)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Hele-Shaw Cell / Correlated Soft Materials / Viscous Fingering / Saffman-Taylor Instability / Modified Darcy's Law / Bubble Motion / Strouhal Number / Karman Flow |
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| Research Abstract |
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.
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