This research investigates a multiphase fluid system involving water, air and its influence and behaviour of the thin aluminium foil which undergoes deformation encompassing in fluid structure interacting study. The study employs a three-dimensional numerical model developed using COMSOL Multiphysics (version 6.2), utilizing the Arbitrary Lagrangian-Eulerian (ALE) framework in conjunction with the Two-Phase Flow, Phase Field interface. The model is built around a block-shaped enclosure containing a thin aluminium foil structure, positioned centrally, with water initially occupying the left region and air distributed elsewhere. The simulation tracks the deformation of the fluid interface as well as the structural displacement of the aluminium foil over time dependent investigation. To manage the computational complexity of this problem, the study focuses on involving moving mesh deformation specifically around the aluminium baffle, while the surrounding fluid domain is treated as rigid. This approach allows for a more efficient simulation without compromising the accuracy of the fluid-structure interaction near the obstacle. The results provide detailed insights into the pressure distribution surrounding the aluminium foil, the von Mises stress experienced by the structure, and the temporal variation of the water volume. The findings highlight the significant influence of the heavier fluid on the structural deformation of the foil and provide crucial data on the interaction between the fluid flow and the structure. This work serves as a valuable reference for researchers engaged in the study of FSI in multiphase fluid systems, offering a computational framework for analyzing complex fluid dynamics and structural responses.