Study On Full-Scale Speed Prediction Method And The Verification By Container Ship Speed Trial

The maximization trend of the transport ship gradually speeds up with the increasing loading requirements of maritime transport and the continuous development of marine science and technology. Speed, as one of the most important parameters of ship, is concerned by ship yard and ship owner from the very beginning of design to the end of construction. The method for prediction of full-scale speed is required in order to complete requirements on speed in ship design specification during design period. The method for verification of full-scale speed is required in order to deliver ship to ship owner after construction. These two methods are essential for the design and construction of transport ship. Therefore, it is necessary to conduct in-depth study on transport ship speed prediction method.There are two full-scale speed prediction methods, one is based on ship model tests, the other is based on CFD. Ship model tests prediction method is still the main prediction method for its higher prediction accuracy, although it has high cost and time-consuming. CFD method also improves rapidly with the development of computer and computing technology. The range of CFD applications is getting more and more widely. Nowadays, CFD prediction method has become an important adjunct to full-scale speed prediction.Ship speed prediction results should be verified by full-scale speed trial. Thus, full-scale speed trial and data analysis method are important to verify full-scale speed and power performance and full-scale speed prediction accuracy.In this paper, the study mainly includes the following four parts:(1) Study on full-scale speed prediction method based on ship model testsThe study focused on the form factor numerical method according to the ship model resistance test results. A new method which adopts an expression of wave making resistance coefficient based on conversation of energy is proposed. The prediction results using the form factor derived from proposed method have higher prediction accuracy through container ship full-scale speed trial verification.(2) Study on full-scale speed prediction method based on CFDBecause the original three-dimensional CFD prediction method has resistance superimposed issue, the results of viscous resistance lack precision. An improved three-dimensional CFD prediction method is proposed by correcting viscous resistance. It can improve the calculation accuracy of the total resistance coefficient and the form factor. The prediction results of the improved three-dimensional CFD method have higher prediction accuracy and can meet the project accuracy requirements through container ship model resistance test and full-scale speed trial verification.(3) Study on full-scale speed trial operationThe study focused on the difficulty to accurately determine the speed is stabilized by manual operation. A DGPS maximum speed prediction method based on AR model in full-scale speed trial is proposed. The prediction results can achieve enough accuracy when the sea condition is under3level of Beaufort wind scale.(4) Study on full-scale speed trial data analysis methodThe study focused on a reasonable analysis method which is more suitable for practical operation in shipyards. The new method is derived from a comprehensive analysis of the shipyards, BSRA, ITTC and ISO methods. Through the verification by21same series container ships,106full-scale speed trials data analysis, the results of proposed method is more accurate and reasonable. It can meet the actual needs of the shipyards and shipowners.Finally, one integrate full-scale speed trial procedure and data analysis method is given. It can be used by ship design and construction units as a reference.