A.Ì.Serdjuchenko Nonlinear motions of the bodies floating on the water-wave surface |
Applied hydromechanics, Vol. 3 (75) ¹ 4, (2001) |
| Nonlinear equations describing finite amplitude motions of rigid bodies which are floating on the wave surface has been derived. Two kind of bodies : 1) 3D multi-elements bodies like SWATH ships and 2) monohull elongated ones are considered. The body motion is sustained by the incoming regular system of finite amplitude progressive Stokes waves. For the 3D bodies the Eulerian form of equations has been used and hydrodynamic loads have been splitted into the nondisturbed by the body motion Krylov-Froude wave loads and hydrodynamic Haskind-Newman loads describing perturbations in the fluid by the diffraction effects and body oscillations. The Haskind-Newman loads ware evaluated by the approximate techinque based on the calculations of generalized hydrodynamic characteristics - added masses and damping coefficients for the instent immersed in the waves part of the body surface. For the monohull alongated bodies for which the longitudinal strength is an actual problem too the gaverning equations have been derived alternatively by using the equlibrum conditions of free-free floating beam. Finally the guverning equations have been introduced in canonical form within the generalised inertia, damping and rigidity matricis and vector of exiting forces. Typical numerical results of nonlinear ship motions in waves are considered. Strong influence of ship bow emegense and immersion into the waves on the amplitudes of the longitudinal ship motion are achived. |
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| TEXT LANGUAGE: Ukrainian |