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Container Ship (container + ship)
Selected AbstractsComputation of turbulent free-surface flows around modern shipsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2003Tingqiu Li Abstract This paper presents the calculated results for three classes of typical modern ships in modelling of ship-generated waves. Simulations of turbulent free-surface flows around ships are performed in a numerical water tank, based on the FINFLO-RANS SHIP solver developed at Helsinki University of Technology. The Reynolds-averaged Navier,Stokes (RANS) equations with the artificial compressibility and the non-linear free-surface boundary conditions are discretized by means of a cell-centred finite-volume scheme. The convergence performance is improved with the multigrid method. A free surface is tracked using a moving mesh technology, in which the non-linear free-surface boundary conditions are given on the actual location of the free surface. Test cases recommended are a container ship, a US Navy combatant and a tanker. The calculated results are compared with the experimental data available in the literature in terms of the wave profiles, wave pattern, and turbulent flow fields for two turbulence models, Chien's low Reynolds number k,,model and Baldwin,Lomax's model. Furthermore, the convergence performance, the grid refinement study and the effect of turbulence models on the waves have been investigated. Additionally, comparison of two types of the dynamic free-surface boundary conditions is made. Copyright © 2003 John Wiley& Sons, Ltd. [source] Architecting a System of Systems Responding to Maritime Domain Terrorism by Orthogonal Array ExperimentNAVAL ENGINEERS JOURNAL, Issue 1 2009THOMAS HUYNH In this work we solve the problem of architecting a conceptual, cost-effective, near-term system of systems (SoS) to respond to terrorist threats to the United States emanating from the maritime domain. The threats include a weapon of mass destruction smuggled on a container ship, a commandeered ship used as a weapon, and small boats used by terrorists to attack maritime commerce traffic and critical shore infrastructures. We formulate the problem as an assignment problem, which is then solved using the orthogonal array experiment. The optimality of the resulting SoS architecture is validated against a heuristically developed architecture and an optimal effective, but not necessarily cost-effective, architecture obtained also with the orthogonal array experiment approach. The principal results of the orthogonal array experiment method reported herein underline this successful exploratory work in architecting an SoS. This method can be extended to architecting of other systems of systems. [source] Practical Hydrodynamic Design of Bulbous Bows for ShipsNAVAL ENGINEERS JOURNAL, Issue 1 2005R. Sharma Although in modern times, bulbous bows have become an integral part of commercial ships, the hydrodynamic design of bulbous bows is still difficult because of costly tank tests and patent-driven knowledge banks. The design of a bulbous bow is needed even at the preliminary design level to predict speed and power. In this work, a design method is presented that combines and extends two famous theories i.e., Kracht (1978a) and Yim (1980) for a particular set of requirements within a narrow range of parameters. The method uses a reanalysis of an approximate linear theory with sheltering effect for resistance estimation, and re-correlation with statistical analysis via a non-linear multivariate regression analysis from existing literature and tank test results available in the public domain. The optimization of design parameters has been done for the design speed. The effect of change in the speed has been discussed and suit-ably incorporated in the design process. In the present work, the effect of production constraints on the design of bulb parameters has also been briefly examined. The results of this study are presented in the form of design parameters related to main hull parameters for a set of input data in a narrow range. The first six parameters have been derived by re-correlation with statistical analysis and the seventh parameter by reanalysis of an approximate linear theory with sheltering effect for resistance estimation. Finally, a design example, which includes tank test results, of an additive bulbous bow for a container ship has been presented. [source] Factors influencing densities of non-indigenous species in the ballast water of ships arriving at ports in Puget Sound, Washington, United StatesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 3 2009Jeffery R. Cordell Abstract 1.Oceanographic characteristics and the presence of international shipping in Puget Sound, Washington, USA contribute to its vulnerability to non-indigenous species (NIS) invasions. To evaluate NIS arriving in ballast water, zooplankton was sampled in 380 ballast tanks of ships after they entered Puget Sound. 2.Taxa were classified into a higher risk group of coastal organisms (including known NIS), and a lower risk group of largely oceanic species. Most ships reported conducting mid-ocean ballast water exchange (BWE). However, despite state regulations requiring BWE, and apparent compliance by ship operators, most sampled tanks from both transpacific and coastal routes had coastal zooplankton densities exceeding internationally proposed discharge standards. 3.BWE efficiency models and controlled before-and-after BWE experiments indicate that BWE consistently removes most coastal zooplankton. However, this study found that although the empty,refill method of BWE significantly reduced coastal plankton compared with un-exchanged tanks, the flow-through method did not, and in either case remaining coastal plankton densities presented appreciable risks of introducing NIS. 4.Densities of high risk taxa were consistently and significantly higher from US domestic trips dominated by tank ships carrying ballast water from California, and lower in samples from trans-Pacific trips dominated by container ships and bulk carriers with ballast from Asia. These findings are probably a result of the dense and diverse NIS assemblages present in California and other US west coast estuaries and the comparatively short transit times between them and Puget Sound. 5.While it appears that BWE can effectively replace NIS with less risky ocean species, new reporting, verification, and operational procedures may be necessary to enhance BWE efficacy. In the long-term, the introduction of ballast water treatment technologies may be required to significantly reduce the discharge of risky organisms from commercial ships if BWE practices do not become more effective. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||