The interest in the simulation of flows around moving bodies is rapidly growing. Examples are: car overtaking, machineries, trains, and applications such as the manoeuvring of racing boats. Such an interest is discouraged however by the inadequate technology made of a number of ingredients: stationary and moving grids, possibly overlapping, and morphing.
These techniques have constraints and limitations: morphing deteriorates the mesh quickly, and moving grids may come to an end when the bodies come too close to each other, so that costly re-meshing steps becomes unavoidable.
This paper presents the technology that allows the freedom to move. The Immersed Boundary method generates a Cartesian grid automatically and quickly, where the bodies can then be freely “immersed” and can change position in the domain automatically without losing a bit of accuracy.