The immersed boundary method is a numerical technique used in fluid dynamics simulations to model the interaction between a fluid and a solid object. It is especially useful for complex geometries where the shape of the object is irregular or changes over time. In this method, the solid object is represented by a computational grid or mesh that is immersed in the fluid domain. The interaction between the fluid and solid is accounted for by applying appropriate forces at the interface between the fluid and solid. These forces are calculated based on the velocity and position of the fluid and solid objects, and are used to accurately simulate the behavior of the fluid flow around the solid object. The immersed boundary method has applications in a wide range of fields, including bio-fluid dynamics (such as modeling blood flow in the heart), computational fluid dynamics, and engineering simulations. It is a powerful tool for studying complex fluid-solid interactions and can provide valuable insights into the behavior of fluid flows in the presence of solid objects.