|
5. CONCLUDING REMARKS
In this paper, motion equations were derived for 2 ships maneuvering in close proximity within the potential theory under the assumption of rigid wall free-surface. Terms of the added mass and the time derivative, which are zero in case of no presence of other ship, play an important role in the mutual interactions of ships moving in close proximity.
By numerically solving the motion equations, the maneuvering of 2 ferries when one ship overtakes the other and passes away were simulated. Then, the added mass and the interaction forces were calculated by a 3D panel method as a function of the ship position in the time step for solving the motion equations. The collision caused by the hydrodynamic interactions between 2 ferries wa4s realistically demonstrated in case of h/d = 1.2.
It became possible to predict the maneuvering motions of 2 ships when moving in close proximity including the collision behaviors by the method proposed in this paper. As the next step of the study, we will investigate the maneuvering characteristics of ships moving in restricted water in view of the safe navigation.
Fig.7: |
Influence of ship size on the collision in overtaking. |
References
[1] Eda. H.:Directional Stability and Control
of Ships in Restricted Channel, Trans. SNAME, Vol.79 (1971), pp.71-116.
[2] Kijima, K. and Yasukawa, H.: Manoeuvrability
of Ships in Narrow, Waterway, J. Society of Naval Architects of Japan, Vol.156
(1984), pp.171-179. (in Japanese)
[3] Abkowitz, M. A., Ashe, G. M. and Fortson,
R. M.: Interaction Effects of Ships Operating in Proximity in Deep and Shallow
Water, 11th Symp on Naval Hydrodynamics. University College London (1976)
, pp.671-691.
[4] Landweher. L., Chwang, A. T. and Guo, Z.:
Interaction Between Two Bodies Translating in an Inviscid Fluid, J. Ship
Research, Vol.35, No.1 (1991). pp.1-8.
[5] Newman, J. N.: Marine Hydrodynamics.
The MIT Press (1977). pp. 132-140.
[6] Newman, J. N.: The Green Function for
Potential Flow in a Rectangular Channel, J. Engineering Mathematics, 26
(1992). pp.51-59.
[7] Lamb, H. : Hydrodynamics, 6th edition,
Cambridge at the University Press (1932).
[8] Yasukawa, H. and Miyazawa, M.: Crabbing
Performances of a Twin Screw Vessel with Bow Thruster, J. Society of Naval
Architects of Japan. Vol.190 (2001). pp.181-190. (in Japanese)
[9] Tuck, E. O. and Newman, J. N.: Hydrodynamic
Interaction Between Ships, 10th Symp. on Naval hydrodynamics (1974). Cambridge.
[10] Yeung, R. W.: On the Interactions of
Slender Ships in Shallow Water, J. Fluid Mech., vol.85. Part1 (1978). pp.143-159
[11] Cohen, S. B. and Beck, B. F.: Experimental
and Theoretical Hydrodynamic Forces on a Mathematical Model in Confined Waters,
J. Ship Research, Vol.27. No.2(1983). pp.75-89.
[12] Korsmeyer, F. T., Lee, C.-H. and Newman.
J. N.: Computation of Ship Interaction Forces in Restricted Waters, J.
Ship Research, Vol.37, No.4 (1993). pp.298-306.
[13] Liu Zu-yuan and Zhang Xiao-tu: Three-Dimensional
Calculation of Hydrodynamic Interaction Forces between Ship. Based on B-Spline,
Proc. New S-Tech 2002, 3rd Conference for New Ship and Marine Technology. Kobe
(2002). pp.319-326.
[14] Kobayashi, E.: The Development of Practical
Simulation System to Evaluate Ship Maneuverability in Shallow Water, 6th International
Symp. on Practical Design of Ships and Mobile Units PRADS'95. Seoul, Korea (1995).
[15] Hirano. M.: On Calculation Method of
Ship Maneuvering Motion at Initial Design Phase, J. Society of Naval Architects
of Japan, Vol.147 (1980). pp.l44-153. (in Japanese)
[16] Dand. I. W.: Hydrodynamic Aspects of
Shallow Water Collisions, The Naval Architect, J. of the Royal Institution
of Naval Architects, No.6 (1976). pp.323-346
AUTHOR'S BIOGRAPHY
The author is currently an Associate Professor in the Department of Social and Environment Engineering, Hiroshima University. Main research area is ship hydrodynamics. He has MSc and PhD in Naval Architecture from Kyushu University. He has also worked as a research manager at Nagasaki R & D Center, Mitsubishi Heavy Industries.
|
