Research On 9200TEU Container Vessel Bulbous Bow Optimization

In recent years,the shipping company has enormous cost pressure due to the increasing fuel oil price.As everyone knows,a small amount of lower speed will make the fuel consumption decreasing a lot,especially for the high speed container vessel.Many container shipping liners had already lowered their vessel's speed in order to decrease the fule oil consumption then save the operating cost.But when the container ship's speed lowered,the bulbous bow which had been designed for the high speed can't adapt the lower speed sailing trend,it will make the resistance higher at lower speed.So we have to redesign the bulbous bow based on lower speed,in order to decrease the resistance at lower speed,then save the fuel oil consumption and operating cost.The prediction of the ship's resistance is always the key subject in ship engineering field.The main research methods include: theoretical calculation,model test and CFD calculation.With the development of computer software and hardware and the continuous improvement of CFD calculation,its application in the ship engineering field has been more and more widely,and has become the most convenient and fast tool for ship's hydrodynamic performance.This paper takes the 9200 TEU container ship as the research object,select one original hull lines with model test result to cary out the verification and analysis.The CFD software SHIPFLOW had been used for the numerical simulation of viscous flow.High order panel method had been used for the wave resistance calculation,boundary layer theory and the Reynolds Average Navier Stokes equation had been used for viscous resistance.The comparison analysis between the model test result and CFD calculation result had been carried out.The results show that the CFD calculation results and the model test result are very close,the deviation is about 5.3%.In view of 9200 TEU container ship,5 different bulbous bows had been designed and developed using geometric parameter of bulbous bow according to the basic design principle of the bulbous bow and the specific reuest of the Owner,and predicted the wave resistance and viscous resistance of these 5 designs using SHIPFLOW.The final optimized bulbous bow had been decided based on the comparison and analysis of the calculation result as the target to be the minimum ressitance at service commonly used speed.Finally,one ship model had been manufactured based on the final optimized bulbous bow,and also the model test had been carried out.Through the compassion of the model test result and the SHIPFLOW calculation result,we can find that the trend of CFD resistance prediction result and model test result is almost same,and only about 5% deviation of absolute value.It verifies that the feasibility of using CFD software to carry out resistance prediction,then to optimize the bulbous bow.The total resistance and bulbous bow geometric parameters had been compared and analized according to the CFD calculation result,then we found several basic design principles for the bulbous bow design.The calculation and conculusion of this paper can provide some reference for container ship bulbous bow modification and design.