Hydrodynamic performance analysis of a container ship in inland waterway of Bangladesh using 3d numerical simulation

Abstract

There are very shallow water regions in Dhaka-Chittagong route of Bangladesh where inland vessels having draft 3.8 meter or more can not operate at its design speed even on high-tide all through the dry season. This thesis work presents hydrodynamic analysis of a 158 TEU container ship by a 3D numerical simulation using SHIPFLOW software to find out resistance, sinkage, trim and squat and suggests how to operate the vessel in very shallow water regions.

To validate the computational results, a benchmark KRISO Container Ship (KCS) hull is used. Moreover, the flow around a 158 TEU container ship is simulated in deep water at different Froude numbers and the computed results are compared with experimental results for validation.

Then, the flow around 158 TEU container ship is simulated in medium deep, shallow and very shallow water at different Froude numbers to obtain the resistance, sinkage, trim and squat values. The present squat obtained (subtracting deep water sinkage from shallow water sinkage) is checked with the maximum standard squat value. It is seen that the present squat is less than the maximum squat.

Finally, from the calculated values of sinkage and trim, the dynamic aft draft of the ship is predicted for those finite depths of water and it is seen that the aft draft increases for the sinkage and trim effect. The navigable route of the container ship is Dhaka-Chittagong waterway which is the inland waterway of Bangladesh. After checking the hydrographic chart of this waterway, three zones were found where the water depth is less than the dynamic aft draft of the ship. If the ship will run in low-tide time in these three zones the bottom part of the ship structure may be damaged for the grounding effect. As a result, in these dangerous zones, how the ship can operate successfully to avoid grounding is shown in this thesis by reducing her speed at a prescribed limit and waiting for high-tide.