Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1979. / Supervised by Ole Secher Madsen and William D. Grant. Includes bibliographical references (leaves 142-144).

A numerical procedure based upon a boundary integral method for gravity wave making problems is studied in the time domain. The free-surface boundary conditions are combined and expressed in a Lagrangian notation to follow the free-surface particle's motion in time. The corresponding material derivative term is approximated by a finite difference expression, and the velocity terms are extrapolated in time for the completion of the formulations. The fluid-body intersection position at the free surface is predicted by an interpolation function that requires information from both the free surface and the submerged surface conditions. Solutions corresponding to a linear free-surface condition and to a non-linear free-surface condition are obtained at small time increment values. Numerical modelling of surface wave problems is studied in two dimensions and in three dimensions. Comparisons are made to linear analytical solutions as well as to published experimental results. Good agreement between the numerical solutions and measured values is found. For the modelling of a three dimensional wave diffraction problem, results at high wave amplitude are restricted because of the use of quadrilateral elements. The near cylinder region of the free surface is not considered to be well represented because of the coarse element size. Wave forces calculated on the vertical cylinder are found to be affected by the modelled tank length. When the simulated wave length is comparable to the wave tank's dimension, numerical results are found to be less than the experimental measurements. However, when the wave length is shorter than the tank's length, solutions are obtained with very good precision. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1980. / Microfiche copy available in Archives and Science. / Vita. / Bibliography: leaves 196-201. / byLee-Lueng Fu. / Ph.D.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Vita. / Bibliography: leaves 170-173. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1979. / Vita. / Bibliography: leaves 121-122. / by Hsien Wang Ou. / Ph.D.

Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Meteorology. / Microfiche copy available in Archives and Science. / Vita. / Bibliography : p. [323-328]. / Ph.D.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographies. / by Mostafa Ameen Foda. / Sc.D.

Background:  As time moves on hardware is able to tackle heavier and more complex computations in real-time systems. This means that more realistic and stylistic environments can be computed. One of these environments is the ocean. To simulate ocean water in real-time, procedural methods such Gerstner waves and Fast Fourier Transformation (FFT) have been developed.    Objectives: The primary objective of this thesis is to compare two procedural methods that are designed to simulate realistic ocean water waves. Meanwhile, the goal of this thesis is for developers to gain an insight into these two methods used in order to simulate realistic ocean water waves. Additionally, it will also discuss advantages as well as disadvantages with both, which gives developers a thorough understanding of the most appropriate method for implementation.  Methods: FFT and Gerstner waves will be implemented in order to perform comparisons of resources, computation time and Video Random Access Memory (VRAM). The procedural methods will be calculated on the GPU and measured using DirectX 11 query interface. Lastly, the final step is to gather data from the CPU side, and store the metrics for time it took to render a frame and scalability of the displacement maps. \noindent\textbf{Results}.The profiling and experiments showed that FFT is more computationally intensive and requires more VRAM. For scalability, FFT also scales worse in terms of both computation time and VRAM usage. Conclusions: From the results we can conclude that FFT is more computationally heavy and requires more VRAM usage than Gerstner waves. In none of the tests did the computation time of Gerstner waves take longer than FFT. Depending on grid resolution, FFT took 4-16 times longer to compute than Gerstner. Even though Gerstner waves takes less time to compute, for smaller grids, less than 512x512, the difference is less than 0.2ms.

Thesis. 1977. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Vita. / Bibliography : leaves 162-165. / Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND LINDGREN. / Vita. / Bibliography : leaves 203-209. / by Douglas Scott Luther. / Ph.D.