No description available.

Motivated by the motion of a ship in a heavy sea, a mathematical model for the vertical impact of a two-dimensional solid body onto a half-space of quiescent, inviscid, incompressible fluid is formulated. No solutions to the full problem are known, but in the case when the impacting body has small deadrise angle (meaning that the angle between the tangent to the profile and the horizontal is everywhere small) a uniformly valid solution is obtained by using the method of matched asymptotic expansions. The pressure on the body is calculated and is in fair agreement with experimental results. The model is generalised for more complicated impacts and the justifications for the model are discussed. The method is extended to three-dimensional bodies with small deadrise angle and solutions are obtained in some special cases. A variations! formulation of the leading order outer problem is derived, which gives information about the solution and leads to an fixed domain scheme for calculating solutions numerically. A partial linear stability analysis of the outer problem is given which indicates that entry problems are stable but exit problems are unstable to small perturbations. A mathematical model for the effect of a cushioning air layer between the body and the fluid is presented and analysed both numerically and in appropriate asymptotic limits. Finally, the limitations of the models are discussed and directions for future work indicated.

No description available.

It was a year of decisions that heralded the pre-dreadnought era, perhaps the least understood chapter of modern naval history. In March 1889, the Salisbury ministry officially endorsed what later became the Naval Defence Act, which in its final form authorised the largest shipbuilding programme of its kind in the nineteenth century. When it was finally completed five years later, the Royal Navy would have a new fleet based around 10 battleships, 42 cruisers and 18 torpedo gunboats, all of the latest design and at a cost of £21,500,000. Then, in December 1889, the Harrison administration sought legislative approval to adopt a forward offensive naval strategy, complete with a fleet of battleships and armoured cruisers in an unprecedented shift in American naval policy. This strategic rationale provided the intellectual framework to transform the United States into a modern seapower. The purpose of this comparative study is to revisit the decisions of 1889, with the benefit of underutilised archival sources and an innovative research methodology recently embraced by the naval historical community. Whereas prior accounts of these decisions generally assess their historical significance in terms of the naval construction that ensued in the pre-dreadnought era, this thesis focuses instead on the pervasive influence of strategic ideas and how strongly they affected the personalities, institutions and events that shaped the respective outcomes in both London and Washington. That strategic ideas shared among naval officers can be decisive in this regard is the underlying tenet behind the cultural approach to historical naval analysis, which is introduced here to highlight the impact of organisational cultures upon the strategic and force structure choices of military organisations.

This thesis presents a new set of methods to assist the process of ship design for safety with particular reference to collision damage. The study has two principal objectives: " investigations into subdivision aspects of passenger ships to improve their overall survival index " investigations into the subdivision of oil tankers in order to improve the effectiveness against spillage in the event of collision damage. In order to investigate the ship subdivision aspect a damage stability model was needed. A pre-requisite for developing the damage stability software was a robust but flexible method to define the hull and the compartments of subdivision. B-splines have been a popular representationatl ool in computer aided design over the past three decades.T his method, though more complex than other spline techniques such as cubic splines, was adopted with a fourth order basis function in this work. A complete set of spline manipulation libraries and associated numerical solvers were developed for this purpose. In addition to this, a method to define the intersection between the hull and the waterplane in the form of a closed B-spline curve for any given orientation of the vessel in terms of -heel, trim and draught was developed to aid the damage stability calculations. Though the earlier regulations stipulate fixed trim assessments to ease the computational process, it is clearly unsatisfactory and research has confirmed this to be a flawed approach. Free trim calculations on the other hand require an iterative and time consuming process to arrive at the equilibrium trim position for each heel angle. Pawlowski proposed a new method for the stability calculations of a freely floating rig when the unit is arbitrarily orientated to the wind direction. It uses the Euler theorem on the properties of equivolume waterplanes to arrive non-iteratively at the new inclined position. This theory was adapted for use in damage stability calculations and was numerically tested and proved to be sound. Damage stability calculations, though combinatorially large, are also inherently parallel. Parallel Virtual Machines (PVM) is a Message Passing Interface (MPI) developed jointly by ORNL, University of Tennessee, Carnegie Mellon University and the Pittsburgh Supercomputing centre. PVM enables a "virtual configuration" so that a collection of serial, parallel and vector processing machines appear as one large distributed memory computer. PVM was compared with another MPI called Network Linda where the advantage of PVM's user controlled message passing was demonstratedP. VM was used to implement the MJMD Distributed Memory paradigm to exploit this inherent parallelism in damage stability calculations and to obtain speedups. A systematic exploration of the search space for this design problem involves the generation of a large number of internal subdivision configurations. This, coupled with the fact that the design space was multimodal in nature made it suitable to the application of a class of heuristic search algorithms called Genetic Algorithms (GA). A brief description of the mechanisms behind GA is presented along with their mathematical basis in the form of two theorems: the schema theorem and the building block hypothesis. Various techniques for solving constrained optimisation problems with GA was explored. The penalty function method was found to be the most suitable and was finally adopted. The above techniques were applied to the optimisation. of the internal subdivision of passenger ships and cargo ships, oil tankers in particular. For passenger ships, the nature of the 's'-factor formulation on the local index was shown. The multimodal nature of the subdivision problem was highlighted and a GA was used to investigate the optimal subdivision characteristics of the vessel. The 's' factor formulation for cargo ship rules is different to that described by the A. 265 set of regulations for passenger vessels. In addition, the cargo ship rules describe a factor V which accounts for the probabilities of vertical extents of damages. However this formulation does not assign any credit for horizontal subdivision below the waterline. Data on vertical extents and vertical location of damages for cargo ships was collected and analysed in earlier studies done at Newcastle University. This data was used to develop a probability function akin to that developed for the longitudinal extent and longitudinal location so as to give credit for any horizontal subdivisions. The principal objective of this part of the study was to explore the search space for subdivision configurations that would minimize net oil outflow.

Thesis (M.M.A.S.)--U.S. Army Command and General Staff College, 2007. / Cover title. AD-A475 516. Includes bibliographical references. Electronic version available on the Public STINET.

Thesis (Ph. D.)--University of Adelaide, Dept. of Applied Mathematics, 1987. / Includes bibliographical references (leaves 70-72).

Thesis (Ph. D.)--University of New South Wales, 2002. / "a thesis submitted for the degree of Doctor of Philosophy in the School of Physics, Faculty of Science at the University of New South Wales" Also available online.

Project report (M. Eng.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaf 97). Also available via the Internet.

Thesis (M. E.)--University of New South Wales, 2005. / Also available online.