An advanced immersed fluid–structure interaction particle method for cardiovascular applications experimentally validated vs a new benchmark case

Fluid–structure interaction (FSI) is crucial in the numerical simulation of cardiovascular phenomena, where pulsatile blood flow dynamically interacts with highly deformable tissues. High-fidelity FSI approaches have become essential to enhance the understanding of potentially lethal pathologies, assisting diagnosis and development of novel therapeutic solutions. This work presents and experimentally validates a new, totally meshless FSI approach, specifically designed for cardiovascular applications. The method is based on the Lagrangian smoothed particle hydrodynamics (SPH), employing a unified physics to represent both blood and deformable walls, avoiding FSI interfaces. A key advantage of this method lies in its ability to overcome the SPH complex issue in contour management, a common challenge that typically increases the complexity of this methodology in FSI applications. Deformable walls are immersed in the fluid domain, and a buffer region of fluid is defined to handle the structural deformation. For validation, a new FSI benchmark is proposed and analyzed with the particle image velocimetry technique. Tailored to entail the typical complexities of relevant cardiovascular situations, the benchmark involves pulsatile flow interacting with a chamber with deformable curved walls, moving through both filling and emptying phases. Despite its simplified geometry, designed to allow a reliable experimental validation, the structure experiences a field of three-dimensional strains and large volume variations, thereby replicating complexities often associated with more intricate models. Numerical and experimental results show good agreement in terms of fluid velocity field and structural deformation, establishing the proposed totally meshless FSI approach as a reliable tool for complex cardiovascular modeling.