Carried out by means of the numerical solution of the Reynold Averaged Navier-Stokes equations. Focus is on the analysis of the viscous effects on the interference, and its dependency on the Reynolds number. To this aim, numerical simulations were carried out for Re ranging from ~10 6to ~10 8, for two different values of the Froude number (Fr=0.30, 0.45). The analysis is carried out by means of an inhouse parallel unsteady RANS solver, based on a finite volume discretization. The free surface is handled by means of a suitable single phase level set algorithm; moreover, Chimera overlapping grid capabilities have been implemented. Wave patterns, wave profiles, surface pressure and velocity fields are analyzed and comparison is made with the demihull configuration. Dependencies of the pressure and viscous resistance coefficients, as well as of the interference factor on the Reynolds number, is investigated. Verification and validation of the computed resistance coefficients is also performed.
The aim of the present work is the analysis of the flow field around a high-speed catamaran, the focus being the effects of viscosity on interference. The geometry considered is the catamaran Delft model 372, an high-speed catamaran designed and tested experimentally at the Technical University of Delft (see van't Veer (1998a) and van't Veer (1998b)). The analysis of the viscous flow past catamarans is very limited in literature: the prevalent approaches are based on potential flow models to predict the wave interference effect and select the optimal separation between the demihulls (see for example Doctors and Scrace (2003) and Maki et al. (2007)). On the other hand, a considerable amount of towing tank work has been done to measure multihull interference drag associated with variation of longitudinal and transverse position of the demihull.
