Wave Resistance and Numerical Pattern for High-Speed Crafts; Validation of Numerical Results by Model Tests.

Some results from a cooperative research program on high-speed displacement craft conducted by Genoa, Naples and Trieste Universities are described in this paper. Numerical wave resistance and wave pattern calculations by a boundary element method are compared with experimental results deriving from tests carried out in two towing tanks at different scales on some models of high speed marine vehicles. The presented cases are two catamarans and a mono-hull examined in the Froude Number range up to 1.1. The numerical wave resistance has been obtained by both the pressure integration and the wave pattern analysis on a transverse cut downstream the ship. An extension of the numerical method based on a modified Newton iterative procedure to determine the running trim and sinkage is presented, discussed and compared with some of the experimental data. Towing tank tests were carried out with the goal to obtain validation of the numerical results and indications on the resistance components, on the scale effects and on the interference phenomena between the demihulls of catamarans. In this perspective, total resistance, running trim, sinkage and wave pattern analysis based on the longitudinal cut procedure have been examined.