PetIBM: toolbox and applications of the immersed-boundary method on distributed-memory architectures. PetIBM implements immersed-boundary methods to solve 2D and 3D incompressible Navier-Stokes on stretched Cartesian grids using a projection approach. Currently, two immersed boundary methods are implemented: Immersed Boundary Projection Method (IBPM; Taira and Colonius, 2007); decoupled version of the IBPM (Li et al., 2016).