The increased availability of computational resources has transformed the prediction of engineering quantities of interest at the design stage. For ship hydrodynamics, this means analysts are now able to predict the power requirements of a vessel at model-scale with good accuracy, routinely. As ever more intricate analysis methods and tools are developed, it has become apparent that modelling all physical phenomena at full-scale remains unattainable both presently, and in the near future. The difficulty in accounting for the full-scale performance frequently limits analysis to model-scale, causing scale effects. Scale effects arise due to the discrepancy in force ratios a model and the prototype will experience. One main consequence of the presence of scale effects is the difficulty in demonstrating the efficacy of new technologies, such as novel energy saving devices. The naval architecture community is therefore not ready to shed many of the historic assumptions made in the design of vessels. A prime example of this is the hydrodynamic modelling of a ship’s full-scale power requirements. Performing solely numerical simulations to obtain such data is considered risky, and is typically accompanied by model-scale experimentation and/or simulations. This work will focus on scale effects encountered when modelling the towed resistance of a ship at model and full-scale. The reasons scale effects are in many cases tolerated, and the problems they may cause are also reviewed. The only remedy to circumventing the presence of scale effects is to work in full-scale at the design stage, but there are a number of problems in doing so. These issues are also explored in this work, with special emphasis on the bottlenecks in adopting full-scale Computational Fluid Dynamics (CFD) numerical simulations as the only prediction tool used in the design process.
- maritime engineering
- computational fluid dynamics (CFD) models