Solving fluid-structure-acoustic interaction problems with Lagrangian meshfree particle method

The meshfree particle method, which is always regarded as a pure Lagrangian approach, is easily represented complicated domain topologies, moving boundaries, and multiphase media. This work presents a Lagrangian meshfree particle method in solving time-dependent fluid-sturcture-acoustic problems. The transient sound generated from the interaction of a rigid object falling into water is investigated with the smoothed particle hydrodynamics (SPH) method. Firstly, the flow field is computed by solving Lagrangian fluid dynamic equations with the SPH method. After that, the velocity of fluid particles is used to compute the sound source. Finally, the underwater sound generated by the fluid-structure interaction is obtained with an acoustic analogy theory. In order to validate the SPH algorithm, the velocity of the sinking circular object in the water is computed and compared with experimental data. The accuracy and efficiency of the SPH acoustic computation are evaluated, and a comparison of cases with different object sizes is also discussed.