The lattice Boltzmann method has become a valuable tool in computational fluid dynamics, one of the reasons is due to the simplicity of its coding. In order to maximize the performance potential of today’s computers, code has to be optimized for parallel execution. In order to achieve parallel execution of the lattice Boltzmann method, the data dependency has to be solved. And to get good performance, the memory has to be organized for unit stride access. Here we investigate the most known algorithms for lattice Boltzmann, and implement a code which runs on a parallel graphics processor, using a library for parallelization called C++ AMP. Furthermore, we show how the code compares to known solutions of fluid flows to verify the numerical results. The optimized parallel code achieves a speed up of 650 times the un-optimized code, on a current generation high-end graphics card.

As the worlds demand for energy is increasing mostly due to the increase in population, and coal, oil and gas deposits are limited, it is desirable to gather energy from renewable energy sources. Wind energy is a form of renewable energy. Wind turbines have been common on land and near shores for some time, but now one wants to take advantage of the wind resources further away from the coast. As the length from the coast increases, so does the water depth making it necessary to use other foundations than the well-known monopile. In this thesis the “Federal Maritime and Hydrographic Agency” in Germany, also known as Bundesamt für Schifffarth und Hydrographie requires in the standard “Design of Offshore Wind Turbines” that an offshore wind turbine needs to be risk evaluated against a ship tanker of more than 500 MJ in collision energy in order to be classified as collision energy. This is to prevent environmental pollution in form of oil spill. Whether the offshore wind turbine models used in this thesis are collision friendly or not relies on different factors. When the given soil properties are used the analyses show in all cases except one that the offshore wind turbine models can be called collision friendly. The case were it could not be called collision friendly was a case with the small jacket at a water depth of 27 m getting hit by a loaded ship at a column of the jacket, but installing a horizontal brace on this jacket would make it also collision friendly. The effects of soil, water depth and a horizontal x-brace are looked further into in this thesis. If the soil had been stronger it is not certain that the outcome would be the same. When the jackets were fixed to the sea bed, several of the models could collapse in the dangerous direction over the ship. A horizontal brace was seen to have a positive effect when installed on the different jacket models. It seems also that it is more favorable to use jackets at deeper water.