2013 Fiscal Year Annual Research Report
流体-薄膜連成計算によるカプセルのラテラルマイグレーションの解明
| Project/Area Number |
13J04880
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| Research Institution | Tohoku University |
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Principal Investigator |
NIX Stephanie 東北大学, 大学院医工学研究科, 特別研究員(DC2)
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| Keywords | lateral migration / capsule / Stokes flow / boundary integral method |
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| Research Abstract |
Lateral migration is the movement of a deformable particle perpendicular to the direction of a surrounding fluid flow. In cases when the effect of inertia can be neglected, such as in the microcirculation, only the presence of a wall or shear gradient results in the lateral migration of deformable particles such as cells. For example, in blood flow, red blood cells are observed to migrate away from the blood vessel wall, leading to the formation of a cell-free layer near the wall. On the other hand, the migration of white blood cells and platelets to the vessel wall is essential for bodily functions such as immune functions and coagulation to occur properly.
The aim of this research is to clarify the effect of lateral migration with a capsule model for blood cells using a bottom-up approach. In the past year, the following has been accomplished :
1. Clarification of the effect of asymmetrical deformation
Deformable particles migrating near a wall have previously been shown to exhibit an increase in deformation relative to similar particles in an infinite flow, which contributes to an increase in migration velocity. We have confirmed that while an increase in symmetrical deformation leads to an increase in capsule migration velocity, an increase in asymmetrical deformation leads to a decrease in capsule migration velocity.
2. Implementation of viscosity ratio
To investigate capsules with various internal viscosities, non-unity viscosity ratio was implemented.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Investigation into the effects of viscosity ratio and shear gradient on lateral migration was carried out, as expected. In particular, the -range of viscosity ratios that was computed using the current method was much larger than anticipated and greatly exceeds that carried out by previous studies. In addition, we showed that the effect of the wall on lateral migration is much larger than that of a shear gradient.
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| Strategy for Future Research Activity |
In the upcoming year, analysis of the effect of viscosity ratio and shear gradient will be concluded, and then the focus of this research will shift from single-capsule dynamics to the dynamics of many-capsule systems. In particular, the effect of capsule concentration on the lateral migration of capsules with varying physical properties will be investigated in a tube geometry in order to clarify the behavior of blood cells in the microcirculation.
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