Yüzer cisimlerin denizcilik hesapları için CFD uygulamaları

Seakeeping calculations are very complex due to dynamics of fluid and the characteristics of the motions. Two fundamental problems are solved to calculate the seakeeping performance of a vessel. The first of these is the hydrodynamics problem which is about wave exciting force and the other is dynamic problem which is relevant to the motions due to wave exciting forces. Also to obtain the motions in waves, added mass and damping forces of the vessel have to be calculated. Strip theory is one of the most popular methods to predict the hydrodynamic forces and motions. Very accurate results are obtained for conventional ships by the strip theory and a number of software based on this theory are widely used by the shipbuilding and offshore engineering industry around the world. However, as a consequence of development of new ship forms and unconventional offshore structures 3D panel methods have been developed for the cases where the strip theory is not applicable. Rapid development of CFD based hydrodynamic analysis software in recent years has resulted in the application of CFD based computational methodologies for seakeeping problems. The main goal of this study is to show the feasibility of CFD based methods for predicting seakeeping performance characteristics in a mathematically described seaway. For this purpose a typical CFD software (AQWA) based on 3D panel method was selected. Four different case studies are performed to validate the linear seakeeping theory. First, the experimental results of added mass and damping coefficients of rectangular, triangular and cylindrical shaped floating bodies are compared with AQWA results. Second, the results of the calculations by strip theory of a rectangular barge are compared with those obtained by AQWA. The third comparative study is relevant with Series 60 formed ships. In the last study, the results of experiment, which is predicted the motions and accelerations of DTMB 5415 model based on the DDG51 type US Navy Combatant form, are compared with AQWA results. Comments about all studies are presented in CONCLUSION & FUTURE WORKS section.