Analysis And Application Of Immersed Boundary Method To Inflation Process

The immersed boundary method is a new type of computational method which employs Cartesian coordinate to deal with moving curve boundary, quite fit for simulating complex interactions of multi-moving or deforming bodies due to its simple programming and easy implementation. Since it was introduced by Peskin in 1972 to study flow patterns around heart valves, it has evolved into a generally useful method for problems of fluid-structure interaction.After describing standard projection method based-immersed boundary method in detail, we analysed its ability to solve fluid-structure interaction problems with large deformation, and multi-fluid problems. To validate our method(code), we adopt the standard projection method based immersed boundary method to the simulation of some physical problems, including viscous drop deformation in shear flow, the motion of a circular membrane in a lid-driven cavity, bubble rising in viscous fluids under gravity. Our results agree well with earlier results available in the literature, which shows the ability of our codes to simulate fluid-structure problems with large-deformation and multi-material flows with large density ratio.Meanwhile, a two dimensional simplied airbag inflation model, which interacts with its surrounding fluids, is established, and the immersed boundary method is applied for the simulation. The time evolution of its shape changes, its volume, the stretching stress along the airbag and the force acting on fluid by airbag is obtained. These results show that the stretching force is mainly concentrated near the airbag inlet and this can be useful for the engineering design.