A Study on Trim Optimization for a Container Ship Based on Effects due to Resistance
The objective of this paper is to perform trim optimization on a 4250 TEU container ship based on the influence of trim on the resistance by using computational fluid dynamics (CFD) in conjunction with towing tank tests. First, the International Towing Tank Conference (ITTC) procedures were applied to uncertainty analysis of CFD and the CFD procedure was further verified and validated through three representative resistance curves obtained by the tests. Next, a series of resistance curves in different conditions with varied drafts and trims were obtained by the CFD computations for the model to provide data source to analyze the influence of the trim on the resistance. Results indicate that the variation of wave making resistance due to trim dominates that of the total resistance. Finally, the resistance data for the model were converted to the engine power of the real ship. At each speed, the response surface of engine power with respect to drafts and trims was constructed and thus a trim optimization program was developed. The real ship operated under the instruction of the trim optimization program can save energy and reduce emissions significantly.