  This paper presents a novel particle method to compute strongly coupled
incompressible fluid and rigid bodies. The method adopts a velocity-based
formulation and utilizes the linear complementarity problem for the
incompressibility constraint. Since all the constraints for incompressibility,
inter-rigid-body contacts, and interaction between incompressible fluid and
rigid bodies are mathematically compatible, strongly coupled simulation is
achieved using the method, where the shapes of the rigid bodies are represented
by particles as well. The abstract concept of velocity-based constraints is
presented, which generalizes the formulations of the incompressibility
constraint and inter-rigid-body contacts and provides a generic way to achieve
strongly coupled simulation. Several numerical examples are presented to verify
the method, which includes rigid-body computation, hydrostatic pressure,
dam-break computation, and circular parch computation for incompressible fluid,
buoyancy and seesaw computation for interaction of incompressible fluid and
rigid bodies, and complex-scene computation for overall behavior and stability.
