The interaction between the two sets of wave fields generated by the demihulls of catamarans can have a significant impact on their resistance. Capturing the interaction is therefore important for accurately estimating the total resistance of the vessel. In this benchmark study we set out to investigate exactly how accurate we can expect our numerical CFD approach to be for catamaran vessels sailing at displacement Froude numbers where the interaction is important.

For this purpose, a publicly available catamaran hull is selected as the subject of the study. Experimental results for calm water resistance of this hull are also available allowing comparison. The experimental results and details regarding the hull model are available in Suoto-Iglesias et al. 2007 (https://link.springer.com/article/10.1007/s00348-006-0244-4).

The study is conducted for ten speeds ranging from Froude number 0.118 to 0.526, where total resistance, dynamic sinkage and trim are compared against experimental data. The comparison showed that the standard Cloud Towing Tank's procedure for calculating calm water resistance predicts the interaction and its consequence on total resistance well, with the average magnitude of error around 3%, excluding two outliers. With the outliers the average magnitude of error is around 5%. The numerical approach correctly predicts a reduction in resistance at Froude number 0.43, when the positive interference wave crest is near the stern. In the graph below it can be observed that the general trend of the error is well captured.

For the entire study and details, please follow the link below.