狭さく部を有する柔らかいチャンネルにおける内部流れと壁面とのインタラクション : 第 1 報モデリング, 数値解析手法及び流れの基本的特徴(流体工学, 流体機械)

抄録

When a constriction is formed inside a blood vessel, a self-excited oscillation of the blood flow and the vessel surface may occur. Numerical investigation has been conducted for incompressible viscous flows through a 2D channel with a flexible upper wall and a rigid lower wall. The flexible wall possesses mass, surface tension and a dumping factor. An obstacle modeled after the constriction was placed close to the inlet on the lower wall. The interactions of the internal flow and the deformation of the upper wall were elucidated for Reynolds numbers ranging from 800 to 5000. Steady solutions were obtained for Reynolds number below 1000 and unsteady solutions above this value. It was found that at the Reynolds number above 2500, a squeezing motion of the upper wall periodically occurs just behind the obstacle and propagates downstream. The flow rate at the outlet periodically varies due to the unsteady motion of the upper wall. The dimensionless period and the amplitude of the flow rate oscillation increase with increasing Reynolds number.