The 12th International Conference on Hydrodynamics
18 – 23 september 2016, Egmond aan Zee, The Netherlands
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APPLICATION OF CFD CALCULATIONS FOR THE IMPROVEMENT OF PLANING CRAFTS MANOEUVRABILITY MATHEMATICAL MODELS


Go-down ichd2016 Tracking Number 33

Presentation:
Session: Ship hydromechanics resistance V
Room: Room 1
Session start: 14:00 Tue 20 Sep 2016

Diego Villa   diego.villa@unige.it
Affifliation: Genoa University

Michele Viviani   michele.viviani@unige.it
Affifliation: Genoa University

Elena Ferri   elena_ferri@outlook.it
Affifliation: Genoa University


Topics: - Ship hydrodynamics resistance, propulsion, powering, seakeeping, manoeuvrability, slamming, sloshing, impact, green water, - Computational fluid dynamics

Abstract:

The high performance requirements for propulsion systems and the increasing attention on manoeuvring features suggest the need for a thorough investigation about planing hull dynamics, already in the preliminary stages of the boat design. Despite during years a rather large number of studies has been carried out on the topic of planing hull dynamics, very limited data may be found in literature about planing hulls manoeuvrability [1][2]. As a matter of fact, most of studies have been concentrated on the topic of resistance prediction and boat powering, with some attention also on dynamic stability and seakeeping. Considering this, in previous activities a time domain simulator, developed in Matlab-Simulink environment, has been developed at the University of Genoa, at first [3] adopting the 3+3 DOF approach proposed in [1]; in this approach, however, running attitude of the boat is given as a function of the drift angle only, partially preventing the possibility to consider its effect on the manoeuvrability characteristics of the boat. In a successive work [4], therefore, data from [2] have been used in order to extend the model to 4 DOF (adding roll to the usual motions in the horizontal plane) completely interacting with each other and to take into account the effect of trim and rise; results obtained showed a good agreement between numerical calculations and sea trials results. Despite the promising results, discrepancies still exists, moreover the available database of experimental data in literature [2] is only limited to prismatic hulls, thus not considering the effect of more complex shapes. Having this in mind, in the present work a series of direct numerical calculations adopting a commercial RANS code have been carried out, with the aim of investigating the possibility of obtaining part of the data needed for the model, in order to avoid the necessity of previous experimental data. Results of this series of calculations are presented and discussed, allowing to get an insight into the problem and to track the way for the development of a fully numerical model for planing boats manoeuvrability. REFERENCES [1] Katayama T., Kimoto R., Ikeda Y. (2005): “ Effects on running attitudes on manoeuvring hydrodynamics forces for planning hulls”, Int.Conf. on Fast Sea Transp., FAST’2005, June 2005, St. Petersburg, Russia. [2] Henry C.J. (1975):“Calm Water Equilibrium, Directional Stability and Steady Turning Conditions for Recreational Planning Craft”, Report SIT-DL-75-1851, Stevens Institute of Technology, Davidson Laboratory. [3] Altosole, M., Figari, M., Viviani, M. (2009): “6 Dof Simulation of Maneuvering and Propulsive Performance of a Waterjet Propelled Mega Yacht”, 10th Int. Conf. on Fast Sea Transp. (FAST 2009), October 5-8, Athens, ISBN: 978-960-254-686-4. [4] Ircani, A., Martelli, M., Viviani, M., Altosole, M,. Podenzana Bonvino, C., Grassi, D. “Propulsion and steering effects on dynamics of high speed craft”, 10th Symposium on High Speed Marine Vehicles (HSMV 2014), October 15-17, Naples