Numerical Calculation Of The Ship-ship Hydrodynamic Interaction Forces In Restricted Waters

The hydrodynamic interaction between ships is one of the most important research topics of ship's maneuverability,which is closely related to ship navigation safety.The high density of ships sailing in ports and waterways because of the development of shipping industry leads to obvious hydrodynamic interaction between adjacent ships.The collision accidents due to the interaction between ships will bring great loss of life and property,may even lead to severe environmental pollution if a chemical carrier or tanker is involved in the accident.Hence,to ensure the navigation safety,the study on the hydrodynamic interaction between ships has received more and more consideration.In addition,with the development of shipping industry,modern ships become more large-scaled,while most of the navigation areas such as nearshore,estuary,harbor and inland waterway remain almost the same size and appear to be shallow and narrow compared with ship dimensions,and may be regarded as the so-called restricted waters.Because of the effects of the shallow water and bank,the hydrodynamic interaction between ships sailing in restricted waters will be amplified obviously,thus the navigation becomes more unsafety.Therefore,the study on the hydrodynamic interaction between ships sailing in restricted waters becomes more important.The CFD software FLUENT is applied to numerically study the hydrodynamic interaction between two ships during encountering and overtaking in restricted waters,including a ship passing by a berthed ship.The unsteady RANS equation in conjunction with the RNG k-? turbulence model is solved to simulate the 3D unsteady viscous flow,and to calculate the hydrodynamic interaction forces on two real ships traveling along parallel courses under the model scale.The relative motion of ships is dealt with by the dynamic mesh method and UDF.Firstly,the feasibility and effectiveness of the proposed method are verified by comparing the numerical results with experimental data,and the regularity of the hydrodynamic interaction forces between two ships during encountering and overtaking are analyzed.Then systematic calculations are conducted for four kinds of ship types at different water depth,ship-bank lateral distances,ship speeds and ship-ship lateral distances,and the numerical results are compared and analyzed to investigate the influence of these factors on the hydrodynamic interaction forces.The numerical results obtained in this paper can qualitatively and reasonably predict the ship-ship hydrodynamic interaction,which has a certain guiding significance to the safe maneuvering and control of ships sailing in restricted waters.The numerical results can also give a reference to further study on the hydrodynamic interaction between ships or ship and other ocean structures under more complicated conditions.