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Item type:Publication, Access status: with files , Design of a high efficiency podded drive for improved course keeping(Norwegian University of Science and Technology, Department of Marine Technology, 2024-04-04); ; ; The design of modern podded propulsion solutions is dominated by merging different, partly counteracting requirements at widely spread operating conditions. Whereas high propulsion efficiency is the key factor, large steering forces at small azimuth angles while maintaining reduced azimuth torque are of importance for a safe navigation with reasonable azimuth unit and bearing sizes. The paper introduces the approach to consider the different requirements in the early stage of a pod design of the SISHIP SiPOD 17M by application of numerical methods. Over a period of more than 25 years, the Potsdam model basin has developed optimizing methods for pods using series of model tests and numerical calculations to achieve an integral description of the interactions of propeller and housing. The numerical method is demonstrated by presenting the propeller design tool VTXopt with an optimization procedure designed as an inverse method. Enhanced numerical calculations using a RANS solver demonstrate the consequences of different fin and strut configurations on course-keeping and maneuvering. An improved steering capability with an attached fin at the cost of larger azimuth torque at small azimuth angles is observed, whereas the azimuth torque at large angles is reduced. The results are validated by model tests at the SVA Potsdam GmbH (SVA).Publicationtype: Conference Paper31 83 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Numerical and experimental study of a series of contrarotating propellers(Norwegian University of Science and Technology, Department of Marine Technology, 2024-04-04); ; ; ; The authors conducted development and analyses of a new series of contrarotating propellers (CRP) as part of a research project funded partly by the Norwegian Research Council and led by the propeller manufacturer Brunvoll. The paper describes the initial investigation for choosing the design matrix, method used for the design of the propeller geometries, potential and CFD based numerical analyses, and open water as well as cavitation model experimental investigations. The main idea behind this new series is to utilize the capability that rate of revolution of the fore and aft propellers can be adjusted independently providing more operational flexibility and better overall efficiency over a wide range of operational conditions. Initial designs were performed using a numerical tool based on potential flow; however, some designs were refined based on analyses performed using CFD. A set of propellers were tested both at SINTEF Ocean and SVA Potsdam. The paper presents the methodology used for the design as well as numerical and experimental investigation of this series. Results are provided graphically. Comparison between results from different numerical methods and the model tests are shown and possible deviations are discussed.Publicationtype: Conference Paper44 48