Numerical Calculation Of Ship Sinkage And Trim In Restricted Water

When the ship is underway, the phenomenon of hull sinkage and trim happens, which is more severe in restricted waters. With the gradual improvement of modern shipbuilding technology, the ship’s enlargement and fast leads to the hull sinkage and trim more severe, threats to the safety of navigation.At present, most scholars of the world using the method of experienced formulas to study the hull sinkage and trim problem. This method’s application scope is limited, the cost of experiment is high, the period of the experiment is long, and what’s more, it has the problem of scaling effect. In recent years, with the rapid development of computer science and technology, numerical calculation method of computational fluid dynamics has a successful application in the ship hydrodynamics problems, and provides an effective tool for ship maneuvering problems.This paper chooses the Series60hull (Cb=0.6) ship model as the calculating model which has been recognized by ITTC and has been tested by a lot of detailed experiments. The hull sinkage and trim is numerical calculated by using the overset grid technology and RANS equations based on the PISO scheme. The SST k-ω model is chose as the turbulence model. Numerical discretization method is the finite volume method. The free surface is simulated with single phase Level set method. Simulation results, model towing tank test results are compared. The results are in good agreement, proving the method’s feasibility and reliability. Moreover, by comparing with calculation results using experienced formulas, shows the numerical method is much more accurate in calculating the hull sinkage and trim than the experienced formulas.This paper carries on the analysis to the influence on hull sinkage and trim of ship speed, shallow water, bank factors. Hull sinkage and trim is numerical calculated when the ship is sailing in shallow water, deep water respectively of different water depth Froude number. Obtain the results of hull sinkage and trim. And the results are compared with the results of restricted waters to explore the influence of ship speed, bank and shallow water on hull sinkage and trim respectively.This paper’s numerical method can calculate the hull sinkage and trim when the ship is underway. This study has a certain reference value for using the computational fluid dynamics method to predict the ship maneuvering performance.