No description available.

A particular problem that has been encountered in modelling the forces and moment acting on a manoeuvring ship, has been the correct estimation of the distribution of side force along its length. If traditional slender body theory is used, reasonable agreement can be obtained between theoretical and experimental result over the forebody of the ship. However, moving aft, the two increasingly diverge until there are significant differences at the stem. For this reason manoeuvring coefficients cannot be accurately predicted by this approach. In a number of studies, the reason for the discrepanciesh as been attributed to the influence of trailing vortices that develop along the hull. The conclusion is consistent with sensitivity analyses carried out with augmented slender body theory incorporating vortices of specified location and strength along the ship. The present thesis is concerned with modelling trailing vortices along a ship in drift motion so that they can be used in the calculation of the associated distribution of forces and manoeuvring coefficients. A numerical model based on the Discrete Vortex Method has been developed for the analysis of vortex flow around the ship which is representedb y slender body approximation. The trailing vortices are modelled by a series of transverse two-dimensional multi-vortex solutions marching longitudinally down the hull. Results are presented for six different hull types; a flat plate, the Wigley hull, a block hull, a Series 60 hull, the British Bombardier and the British Bombardier with a pram stem. The effects of varying drift angles are also investigated for each hull types. Good qualitative agreement is shown between the predicted velocity and vorticity fields and results from experimental studies. The distribution of side forces and yaw moments along the hull is also well predicted. The results explain manoeuvring phenomena occurring for the hull forms considered that have been observed experimentally and at full scale.

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The behaviour of the hydrodynamic loading experienced by a circular cylinder in the presence of boundaries has been the subject of investigation by various investigators in recent years. Amongst other things it is relevant to the design of offshore structures and subsea pipelines. It is important to be able to assess the behaviour of such components of an offshore structure because it has to be designed to withstand loading due to flow interactions which are complicated in nature and not yet fully understood. To gain a clearer insight into the effects of anodes on the overall loading of an offshore structure, for example, the local flow around a cylindrical member in the presence of boundaries must be understood. In the present study, a numerical model based on the Discrete Vortex Method has been developed as a means of analysis of such flows since, in comparison to experimental methods, it is a less expensive and less time consuming approach in gaining that knowledge. The algorithm is developed in such a way as to enable application to a range of cylinder / cylinder, cylinder / anode, and cylinder / wall configurations subject to a variety of steady and time dependent flows. The technique has been applied in a number of case studies which include the investigation of the flow interactions occuring when two cylinders are in close proximity and also when a cylinder is close to a plane boundary. The engineering applications are the interference of structurel members, the loading on structural elements due to the presence of anodes, and the loading on free spanning subsea pipelines. The in-line and transvese force coefficients arising from the case studies and also the flow patterns obtained are presented in order to provide a more detail description of the flow phenomena and interactions involved. The comparison of the results with both experimental and numerical evidence is also presented and the range within which the algorithm produces good results is identified.

No description available.

No description available.

Thesis (PhD)--University of Western Australia, 2004.

Thesis (Ph.D.)--University of Western Australia, 2004.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 101-105). Also available via the Internet.

Thesis (Ph.D.)--University of Western Australia, 2007.