Flow-structure interaction of the parachute in inflation process

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The parachute has a strong flexibility because it is made of a fabric. Therefore, the instantaneous shape is formed by the difference between within and outside it. It is so hard to analyze the fluid-structure interaction for the parachute because of the flexibility. Even if we would apply for the rigid parachute as a first order approximation, we happen to meet the strong non-linearity between the body and the wake. In this investigation, the dynamic motion of it is focused by using the numerical simulation and the water tunnel experiment, in which the flow fluctuations around the parachute are focused.First, the parachute is assumed as a rigid rounded hemisphere body, in which it is not deformed. The motion of the parachute shows the pendulum motion, in which the virtual mass (added mass) effect plays an important key because of the accelerating motion. In order to get data precisely, the high accuracy simple approximation method is proposed to apply for it.In order to catch the inflation process of it, the 2 dimensional numerical simulation has been carried out. When the folded parachute is inflated, the snatched force is caught in detail in our simulation.Second, after the effect of the virtual mass and the flexible wall model are discussed, the 3 dimensional simulation has been carried out. The flow structure is clarified by he numerical results together with the experimental results (flow visualization). The oscillation patterns of it are classified into three categories (lineal ; arc, circular motions). Furthermore, the guide of the parachute study into future is shown.