The results of computational fluid dynamics (CFD) are significantly affected by the mesh and the numerical methodology chosen by the users. In this study, to overcome the mesh dependency by users, a macro that automates mesh generation and simulation settings is developed using an open-source CFD library, OpenFOAM. The main goal of a developed macro is to accurately predict the calm water resistance of the ships. The computation is conducted for two types of ships, KCS and KVLCC2. An uncertainty analysis is performed for the mesh and the appropriate mesh size is selected. Then, validation is conducted by comparing the computation results to the experiment for different ship speeds. From the obtained results, it is found that the uncertainty according to the user can be reduced and the preparation time of the simulation can be significantly reduced through the developed macro.
Calm water resistance is a key factor in designing a ship. This is because it is directly related to the operation efficiency of the ship and the cost problem. Many people strive to reduce ship resistance for high operational efficiency and the economy of resources. Therefore, efforts have been made to accurately predict calm water resistance from before. In the past, predictions were made through model experiments, but predictions through CFD are becoming the main focus due to the development of computers and technologies. However, uncertainties arising from various factors such as physical properties, turbulence models, mesh, numerical scheme, etc., occur in CFD calculation, and it is important to control them. Among them, uncertainty about the mesh is the main research point in this paper.
Although CFD calculations are made using the same object as the model, the number of mesh and the method of refinement of the mesh are inevitably set differently for each person. As a result, there is a high possibility that the results will vary widely for each user. To address this problem, a mesh generation macro is one of the solutions. By using the macro, it is possible to generate a consistent mesh regardless of the user and may lead to consistent results.
