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Joint Industry Project Tripping now running

Date
Oct 24 2024
Reading time
3minutes
The Tripping JIP is an investigation into the full-scale performance of ship propellers. The objective is to create better and more reliable full-scale predictions of the performance of propellers, either using model tests or full-scale RANS computations.

The Tripping JIP aims to narrow the gap between model tests and CFD predictions. The main idea is that CFD will not be adapted towards model scale measurements using transition modelling, but that model tests will be adapted towards standard CFD computations using turbulators to trip the flow. This approach significantly decreases the uncertainty of both the CFD and the model tests.

The approach is to trip the flow on the model scale propellers, such that the flow will be turbulent, resembling the full-scale situation. As such, the experimental uncertainty due to laminar flow effects is avoided. And second, new accompanying scale corrections (for only the mere viscosity effect on turbulent flow) with standard RANS computations (without transition modelling) need to be determined.
MARIN Tripping JIP

FULL DATASET AND WIDE RANGE OF TEST FACILITIES

In the Tripping JIP, MARIN will test and compute a large set of propellers. This dataset shall be used fourfold. First, to provide benchmarks for CFD on propellers. Second, to develop new generic scale corrections for propellers to be used in model test. Third, to develop new generic CFD correlations for propellers to be used for numerical powering predictions. And finally, to provide input to develop new full-scale polynomials for the performance of the renown Wageningen C and F series.

Six other research institutes are working together with MARIN to not merely investigate open water characteristics of propellers, but also to study propulsion tests in combination with tripping.

The Tripping JIP will present new propeller scale corrections and propose updated procedures for extrapolating propulsion tests to the ITTC. The project is a significant collaborative effort, bringing together shipowners, research institutes and the industry to create a level playing field.

BENEFITS

The benefits of the Tripping JIP include reducing unexpected outcomes during model tests by improving the tests themselves, updating the extrapolation methodology, and adopting reliable CFD-based propeller scale effects. Besides more reliable full-scale predictions, designers will have better control of the propeller design on both model scale and full scale. This would allow to direct the design focus to full scale, without being severely limited by model scale limitations, ultimately leading to improved propeller designs for full scale. Furthermore, the Tripping JIP will quantify of the effect of surface roughness on propeller performance. Moreover, benchmark data for RANS computations on propellers for reference and quality checks will be provided, such that the quality of and confidence in CFD and computational design methods will improve significantly. Finally, the Tripping JIP will provide full-scale data to the Wageningen C and F series.

INTERESTED TO JOIN?

The Tripping JIP is eager to welcome new participants. The 3-year project started in April 2024 and is still open for participation.
For more information see www.marin.nl/jips/tripping
MARIN Tripping JIP participants