This study offers an interesting reflection and presents some original features in the calculation of the ship’s hydrodynamic derivatives and interaction factors. The main purposes of this work are: a Provide an overview of the complete calculation sequence from the conduction of virtual captive tests to manoeuvre simulation. Virtual captive tests are carried out by developing a simplified and innovative procedure to reduce the computational effort; b Extend and validate the calculation procedure of captive tests with roll angle. From these results, the coefficients for 4 DOF model are calculated and the effect on manoeuvre prediction is analysed; c Provide and validate numerical calculation methodologies for the main interaction factors (propeller - rudder and hull - propeller/rudder) and show the comparison between CFD coefficients and theoretical (or semi-empirical) ones implemented in the DITEN manoeuvre simulator; d In all cases, results from CFD are used in order to compare with results from semi-empirical models developed during years at DITEN, with the aim of acquiring an insight into the capability of both methods (CFD and semi-empirical) and their merits and shortcomings; furthermore, CFD results may be adopted, especially when applied systematically, to improve semi-empirical methods;
Manoeuvrability Assessment of Twin Shaft Ships by means of Open-Source Code
FRANCESCHI, ANDREA
2023-05-05
Abstract
This study offers an interesting reflection and presents some original features in the calculation of the ship’s hydrodynamic derivatives and interaction factors. The main purposes of this work are: a Provide an overview of the complete calculation sequence from the conduction of virtual captive tests to manoeuvre simulation. Virtual captive tests are carried out by developing a simplified and innovative procedure to reduce the computational effort; b Extend and validate the calculation procedure of captive tests with roll angle. From these results, the coefficients for 4 DOF model are calculated and the effect on manoeuvre prediction is analysed; c Provide and validate numerical calculation methodologies for the main interaction factors (propeller - rudder and hull - propeller/rudder) and show the comparison between CFD coefficients and theoretical (or semi-empirical) ones implemented in the DITEN manoeuvre simulator; d In all cases, results from CFD are used in order to compare with results from semi-empirical models developed during years at DITEN, with the aim of acquiring an insight into the capability of both methods (CFD and semi-empirical) and their merits and shortcomings; furthermore, CFD results may be adopted, especially when applied systematically, to improve semi-empirical methods;File | Dimensione | Formato | |
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