International Shipbuilding Progress - Volume 53, issue 1

Authors: Liut, Daniel A. | Lin, Woei-Min

Article Type: Research Article

Abstract: A Lagrangian vortex-lattice approach is presented, through which bodies of arbitrary shape, wakes shedding from them, and a free surface can be modeled using sheets of concentrated vorticity. The method accounts for a full interaction of all vortex sheets in the time domain. A damping beach is used on the external boundaries of the free-surface domain. Multiple time-step computations combined with a versatile gridding approach make the current numerical implementation suitable for solving a wide variety of hydrodynamic and low-speed aerodynamic problems. Several examples and comparisons with experimental data are presented.

Citation: International Shipbuilding Progress, vol. 53, no. 1, pp. 1-32, 2006

Authors: Tarafder, Md. Shahjada | Suzuki, Kazuo

Article Type: Research Article

Abstract: This paper presents a potential based boundary element method for solving a nonlinear free surface flow problem for a ship moving with a uniform speed in shallow water. The free surface boundary condition is linearized by the systematic method of perturbation in terms of a small parameter up to second order. The surfaces are discretized into flat quadrilateral elements and the influence coefficients are calculated by Morino's analytical formula. Dawson's upstream finite difference operator is used in order to satisfy the radiation condition. The second order solution gives better result than the first order solution. So the present method with …the second order solution can be adopted as a powerful tool for the hydrodynamic analysis of the thin ship in shallow water. Show more

Keywords: Finite depth, wave making resistance, potential based boundary element method, perturbation method, Dawson's finite difference operator

Citation: International Shipbuilding Progress, vol. 53, no. 1, pp. 33-54, 2006

Authors: Varyani, K.S. | Krishnankutty, P.

Article Type: Research Article

Abstract: Harbour is a region where ships are moored in a relatively calm environment, but it is a region with dense ship traffic. Present study deals with analysis of forces and moment on a moored ship induced by a ship passing-by. The elasticity of a mooring rope depends on the material, construction, length and diameter of the rope. Fibre ropes are more elastic than steel ones. The effect of these factors of mooring system on drift motions of the moored ship are presented here for different combinations of mooring rope materials and lengths for a selected vessel combination and operating condition …with the breaking strength requirement keeping constant. The mooring system used is a linear one and the coupling between modes of motion of the moored ship is neglected. Show more

Keywords: Hydrodynamic interaction, moored ship, ship induced motions

Citation: International Shipbuilding Progress, vol. 53, no. 1, pp. 55-71, 2006

Authors: Motok, M.D. | Rodic, T.

Article Type: Research Article

Abstract: The pontoon bridge, or so called The Bridge on the Barges, consisting of longitudinally connected standard inland barges, was to be built on the river Danube. The first step of the structural design was to evaluate vertical displacements and forces at the points of hinge connection of the barges, for various cases of traffic load distribution along the bridge. Instead of performing standard hydrostatic calculations of immersion and trim of the vessels, whole structure was modeled as a chain of rigid beams elastically supported by buoyancy – and analyzed using the finite element method.

Citation: International Shipbuilding Progress, vol. 53, no. 1, pp. 73-82, 2006