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MAROFF-2-Maritim virksomhet og offsh-2

Flexible propulsors for marine applications

Alternative title: Fleksible propulsors for marine applikasjoner

Awarded: NOK 11.5 mill.

The project has achieved several of its initial goals. Particularly successful from a scientific point of view were the tests with model scale propellers made of resin without reinforcements. The results were made publicly available, and they have been often cited by other researchers since their publication. At least two follow up projects are related to these tests. The results from the tests with the resin propellers were used to validate the simulations that were performed coupling a CFD and a FEM commercial code. The numerical results matched closely the experiments using standard methods and parameters of both codes. Although the material of the blades was homogeneous and isotropic the co-simulation of fluids and structures was validated for propellers. The development of the IGA-BEM code reached the stage where the first calculations on test cases found in literature were carried out giving promising results. Due to the lack of time, it was not possible to validate the code against the data that have been produced by the project it-self. Another activity that proved to be very successful was the construction of a prototype full scale blade. The blade was built and dry-tested to show that under loading it deformed as expected. It was checked whether the material was responding in such a way that it would smooth out the load variations that are inherent to the operation of marine thrusters. The design of the blade was carried in a systematic way showing which strategies designers can use to make composite propellers. Along with the physical blade, a numerical model of the blade was produced. The model was used to perform simulations using the same strategy that proved to be successful for the resin blades. In this case though more difficulties were encountered, especially when dynamic simulations were carried out, showing that there is still room for improvements of the numerical tools and that tailor-made experiments are needed to validate the computational models in non-steady conditions.

The project produced some high quality result in the field of flexible propulsors. Especially the tests with flexible isotropic blades proved to be very successful. Numerical computation with fluid dynamic interaction were extensively adopted and their potential and drawbacks assessed. The ground work for new numerical methods to be adopted in the field was laid. A prototype blade showing the achievements by the projects in terms of design methods was made.

The project tackles the topic of hydroelasticity, both static and dynamic, of azimuthing thrusters with the ultimate goal of improving their performances and reliability. The project comprises experimental work, numerical simulations and design strategies development. The topic of hydroelasticity of azimuthing thrustets has never been addressed in a systematic way in research. The project aims at building such a systematic approach to the topic by: 1) Create a sufficient amount of experimental data in model scale in order to provide validation material for numerical simulations of the hydroelastic response of azimuthing thrusters 2) Develop reliable state of the art numerical models to study the problem and validate them against the experiments 3) Apply the numerical models to the design of thrusters that have their elasticity taken into account at the design stage with the goal of improving their performances. 4) Develop strategies to mitigate the effect of the vibrations that the thrusters must undergo when exposed to dynamic excitation with the goal of improving their reliability. The project is expected to have a large impact both on applied research and industry; in fact, the project will provide the research community with experimental data which is lacking in literature and the industry with methods to include the hydroelastic response of azimuthing thrusters during the design stage. It is believed that the project can play a role in improving the safety of ship operations by improving azimuthing thrusters reliability and in making shipping greener by reducing the fuel consumption.

Funding scheme:

MAROFF-2-Maritim virksomhet og offsh-2