Purjeavusteisen risteilyaluksen suorituskykyanalyysi erotetulla CFD-laskennalla

A sail-assisted cruise ship refers to a cruise ship equipped with both sails and a standard propulsion system. These sail-assisted vessels are gaining attention as a pathway towards a greener maritime industry, yet they introduce challenges in the ship design that not present with conventional cruise ships. In particular, performance prediction in various operating conditions becomes significantly more complex with the addition of sails. This thesis presents a clear framework to overcome computational expense and model complexity to provide a performance prediction model. The performance prediction of a ship provides an estimate of the ship’s performance in different operating conditions. These estimates can be used to define the ship’s maximum speed or power demand for the propulsion devices. The latter is especially crucial as it defines the requirements for the ship’s main engines. The proposed method is based on a decoupled CFD approach, in which each foil is analyzed independently. The decoupled approach allows for greatly reduced computational load while maintaining physical relevance. Governing force and yaw moment equilibrium equations are formulated to couple the foils together. The method was demonstrated with an example sail-assisted cruise ship by solving the required propulsion powers with least squares method. The results were found to be consistent with physical expectations. Main limitations of the approach arise from neglecting the interactions between the foils, as each sail, daggerboard, rudder, and the hull is analyzed independently. In addition, limiting the model to consider only three degrees of freedom adds another error factor to the method. The effect of these limitations on the accuracy of the solutions is unknown as no data for validation purposes is available. However, the order of magnitude of the solutions should remain correct even with these error factors. Despite the limitations, the method allows efficient iterating over design parameters in the early design phases and provides useful preliminary estimates for the ship’s performance. Future research should focus on model validation with experimental data or CFD results, and increasing accuracy by addressing sources of modeling error