Simulation of compressible fluid-elastic solid interactions

A numerical model for studying the interaction between a compressible fluid and an elastic solid is described. The fluid is only slightly compressible, but large pressure changes in the problem (ambient to 50 MPa) require that the compressibility be taken into account. The fluid is treated as barotropic, which means that the pressure is a function of the density alone. It is modeled using a stabilized spacetime finite element formulation which can automatically handle the changes in the size and shape of the computational domain caused by the deformation and motion of the solid. The solid is treated as linearly elastic and is modeled using a Galerkin finite element method. The solid is modeled using classical linear elasticity theory, instead of, e.g., plate or beam theory. This allows the modeling of structures of arbitrary shapes. The coupled model is used to study an interior flow problem in which a defoimable piston controls the size of an orifice through which the liquid flows. The vibration of the piston may have an important effect on the mass flow rate of the liquid.