This paper deals with high speed tests carried out on three geosim models of a catamaran hull and of its hard chine demihull, of a trimaran hull and of its round bilge main hull. The current scaling procedures ITTC 57 and ITTC 78 were applied with the aim to provide a better understanding of appropriate resistance breakdown and scaling for high speed single hulls and multi-hulled vessels. The approach used for the ITTC 78 procedure consists in obtaining a form factor for each Fn by iso-Froude method, then, for each scale, by direct measurement of the wave pattern resistance by a longitudinal cut method, by examining the Ct- Cwp curves at high Froude numbers. This approach was carried out with the goal to obtain validation of form factor determined by running the model bow down (transom emerged) with Prohaska and/or Hughes methods, by enveloping versus Rn the curve of Ct obtained by low speed model tests. In the case of multi-hulls the form factors should include also the interaction among the hulls. A numerical method based on Rankine sources for the evaluation of the wave resistance and of the wave pattern analysis was also applied and a comparison with the experimental results was carried out in terms of wave resistance.

Investigation on Model-Ship Correlation and Power Prediction for high Speed Multi-Hulled Vessels

ZOTTI, IGOR
2002-01-01

Abstract

This paper deals with high speed tests carried out on three geosim models of a catamaran hull and of its hard chine demihull, of a trimaran hull and of its round bilge main hull. The current scaling procedures ITTC 57 and ITTC 78 were applied with the aim to provide a better understanding of appropriate resistance breakdown and scaling for high speed single hulls and multi-hulled vessels. The approach used for the ITTC 78 procedure consists in obtaining a form factor for each Fn by iso-Froude method, then, for each scale, by direct measurement of the wave pattern resistance by a longitudinal cut method, by examining the Ct- Cwp curves at high Froude numbers. This approach was carried out with the goal to obtain validation of form factor determined by running the model bow down (transom emerged) with Prohaska and/or Hughes methods, by enveloping versus Rn the curve of Ct obtained by low speed model tests. In the case of multi-hulls the form factors should include also the interaction among the hulls. A numerical method based on Rankine sources for the evaluation of the wave resistance and of the wave pattern analysis was also applied and a comparison with the experimental results was carried out in terms of wave resistance.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2562512
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