The ComMotion project:Computational methods for moving and deforming objects in extreme waves

Extreme waves and their impact on (fixed and floating) offshore structures have long been subjects that could only be studied with experimental methods; sufficiently accurate existing numerical methods (CFD) are only recently emerging. Phenomena like green water loading and slamming are highly dependent on the relative motion of a ship versus the on- coming wave crests, as influenced by the preceding wave groups. Thus, accurate prediction of the hydrodynamic forces requires methods that can reliably predict the interaction between ex- treme waves and body dynamics. Over the years, the ComFLOW simulation method has been developed to cover this CFD niche. A novel ingredient devceloped in the ComMotion project is an unsteady coupling algorithm that is numerically stable under all circumstances (such as ratio of body mass versus added mass). Also, a new class of absorbing boundary conditions has been extended to include the effects of current. Several applications will be presented, including esperimental validation