Accession Number : ADA321371

Title :   A Combined High-Order Spectral and Boundary Integral Equation Method for Modelling Wave Interactions With Submerged Bodies.

Descriptive Note : Doctoral thesis,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING

Personal Author(s) : Thomas, Gregory R.

PDF Url : ADA321371

Report Date : FEB 1997

Pagination or Media Count : 121

Abstract : The interaction of submerged maneuvering vehicles with the free surface is a topic of importance in ocean engineering. Present methods for estimating the forces and motions due to wave-body interactions are limited in their ability to efficiently compute forces and motions of interest when free surface slopes are steep or body motions are large. Methods are required which contribute to overcoming these difficulties. This thesis presents a method for analyzing the nonlinear interaction of non-breaking waves with submerged bodies of arbitrary geometries undergoing arbitrary motions. The method couples a high order spectral representation of the free surface profile and free surface potential with a boundary element representation of the body to effect a time domain solution for specified initial-boundary value problems. The spectral representation of free surface quantities facilitates the use of fast transform techniques for rapidly computing free surface quantities. The boundary element representation of the body enables bodies of arbitrary geometry to be modeled. Fully nonlinear free surface boundary conditions are used as time evolution equations for the free surface profile and potential. The effectiveness of the method is demonstrated through the solution of three classes of two-dimensional problems: (1) diffraction of incident waves by a stationary cylinder, (2) wave radiation by a cylinder undergoing forced oscillations, and (3) combined diffraction and radiation by a submerged neutrally buoyant cylinder free to respond to incident waves.

Descriptors :   *OCEAN WAVES, *MARINE ENGINEERING, MATHEMATICAL MODELS, MANEUVERABILITY, UNDERWATER VEHICLES, EQUATIONS OF MOTION, HYDRODYNAMIC CHARACTERISTICS, TIME DEPENDENCE, THESES, COMPUTATIONAL FLUID DYNAMICS, FLOW FIELDS, NONLINEAR SYSTEMS, CYLINDRICAL BODIES, BOUNDARY VALUE PROBLEMS, UNSTEADY FLOW, INTEGRAL EQUATIONS, OCEAN MODELS.

Subject Categories : Marine Engineering
      Fluid Mechanics
      Physical and Dynamic Oceanography
      Operations Research

Distribution Statement : APPROVED FOR PUBLIC RELEASE