RANS Analysis of the Interferece Effect in Catamaranse

In this paper the study of the turbulent flow past a fast catamaran is presented with focus on the fluid-dynamic interference between the demihulls. The flow is investigated analyzing numerical results obtained with the Reynolds Averaged NavierStokes code ?navis. The interference between the demihulls increases the catamaran resistance with respect the monohull case, and both pressure and viscous drag components are influenced by the demihulls separation. Comparison between monohull and catamaran flow fields is first shown. Then, the influence of both Reynolds number and demihulls separation on the interference effect, and the multihull resistance is presented. Even though, preliminary resultsshow the complexity of the flow features and the relevance of the analysis for design purposes. According to these results, there is a remarkable scale effect on the multihull resistance.