Analysis of the interference effects for high-speed catamarans by model tests and numerical simulations

This paper presents the results of a large experimental and numerical campaign aimed to the analysis of the interference effect for a fast catamaran. Several separation distances are considered; data for resistance, sinkage and trim are collected by towing tank experiments for Froude number ranging from 0.2 to 0.8. Monohull tests are also carried out, the analysis of the interference and its dependency on the separation length being the main objective of the paper. Resistance coefficient curves reveal the presence of two humps, the second one strongly depending on the separation length; high interference is observed in correspondence of the second hump. It is found that the narrower is the configuration, the higher is the interference and the speed at which this maximum occurs. To gain a deeper insight into these behaviors, a complementary analysis, in terms of wave field, surface pressure and velocity field is carried out by an in-house unsteady RANS solver. Verification of numerical results is provided, together with validation, which is made by the comparison with both present and other experimental data. Agreement in terms of resistance coefficient is rather good, comparison error being always smaller than 2.2%.