A lot of experimental results of KVLCC2 are available from many institutions, as a low speed full hull, squat is observed clearly in experiments, which affects its resistance obviously. Numerical prediction on resistance of KVLCC2 in deep water with squat were extensively reported, while few work could be found in shallow and extremely shallow water. When simulating of flow around ship with squat, fluid domain should deform according to the hull movement, leading to changes of topology of the discrete meshes, if the under keel clearance is small, unphysical grounding may occurs, bring numerical problems in the simulation. In this paper, a numerical approach is introduced to predict squat in deep and shallow waters, and RANS solution is adopted to simulate the flow around KVLCC2. Study in this paper shows its efficiency and stability in solving such problems, especially in the solution in extremely shallow water, also the flow details around the ship with different water depths and different Froude numbers are analyzed and discussed.
Flow details around the ship in shallow water and its hydrodynamic performances are different form that in unlimited water, which is known as shallow water effects. Shallow water effects increase ship resistance and affect ship squat according to the limitation of the water depth, the former decreases ship rapidity performance and leads to cost increase in service, while the latter would cause grounding and bring a safety accident, especially in extremely shallow water, the effects on resistance and squat are more seriously.
Tests in towing tank are generally used in study on shallow water effects, while more and more numerical studies on shallow water effects are published in recent years because of lower economic and time cost, and numerical method also shows its advantages in complex hydrodynamic issues such as self-propulsion (Carrica P M, 2010) and maneuvering performance. SERGE TOXOPEUS used ReFRESCO software to simulate the flow field around the hull of KVLCC2 in different water depths and different heading angle, the numerical results are compared with the experimental data, which verifies the accuracy of the numerical results of ReFRESCO software (SERGE TOXOPEUS, 2011). P Mucha and G Deng used the STAR CCM+ software to calculate the squat of the KCS ship in shallow water, and the difference between the numerical and the experimental results was analyzed to validate the accuracy of the squat prediction in CFD approach (P Mucha and G Deng, 2016).
