This book covers a wide range of numerical computation techniques within the specialized area of fluid mechanics. Numerical computation methods on the effects of fluid on structures are described, with particular emphasis on the offshore application. The book emphasizes the latest international research in the area for the advancement of the interaction problem and new applications of the development to the real world problems. The basic mathematical formulations of fluid structure interaction and their numerical modeling are discussed with reference to the physical modeling of the interaction problems. The state-of-the-art on numerical methods in fluid-structure interaction is included, with emphasis on detailed numerical methods. Examples of the numerical methods and their validations and accuracy check are given, stressing the practical application of the problem. Some interesting results on numerical procedure are cited showing the limiting criteria of the numerical methods and typical execution time.