Investigation of Springing Responses to High Harmonics of Wave Loads by Direct Coupling Between CFD and FEM

Abstract

Abstract Springing of hull girder to very high harmonics of wave loads is investigated thoroughly using one-way coupling with the help of two-way direct coupling between Computational Fluid Dynamics (CFD) and Finite Element Method (FEM). A segmented barge is chosen as a subject model, in which each segment is connected to a backbone. The springing response of the ship model to very high harmonics was reported in the tank tests by the present authors. The coupling platform for exchanging the related information to capture hydro-elastic behavior is developed separately by the authors. First, the numerical methods are compared for rigid body motions, then flexible behavior is studied. In the one-way coupling, the effect of added mass associated with the springing is considered manually by adjusting the total mass of the body. However, in the case of two-way coupling, such manual adjustment is not necessary as the added mass effect is automatically considered in the simulation. In the present paper, the comparison between one-way and two-way coupling together with benefits and drawbacks of individual methods are discussed. Most of the existing literature is mainly focused on the lower order harmonics for the springing phenomenon, however, in this paper possible case of 14th order harmonics is discussed and validated with experiment.