Examples of PROCAL based applications

PROCAL for automated propeller design (PROPAGATE-1,2), as well as for Energy Saving Device designs. The use of PROCAL for flexible composite propellers is another important development, necessitating a coupling of the PROCAL code with a FEM code.

As a result, CRS developments would enable Monique Lorand to produce an optimised design in 24 hours which required only 8 hours of her own time!

No carpenter without a hammer: PROCAL In 2003, MARIN was given the task of developing the BEM code PROCAL. Although work started from scratch, use could be made of multiple BEM codes for propellers that were available at MARIN, as well as knowledge of a BEM developed in cooperation with the University of Lisbon (IST). Important requirements for the PROCAL code were determined to be robustness, low CPU time and easy maintenance. This resulted in a code that could predict unsteady sheet cavitation on propellers operating in a ship wake with

the resulting hull-pressure fluctuations. Simultaneously, the graphical user interface PROVISE was developed by which the user can easily import propeller geometries, generate surface panels, perform computations and analyse results. Hull- pressure fluctuations can be computed by the acoustic boundary element method EXCALIBUR, developed at MARIN.

An important input to PROCAL is the effective wake field of the ship in which the propeller operates. At the beginning of the century, this wake field used to be obtained by a model-scale measured wake field that is made effective and scaled to full-scale Reynolds numbers with the tools developed in the PIF group for example. However, with RANS methods becoming mature in predicting the ship wake field, a coupling procedure between RANS and BEM was developed in the PROPDEV and PROPLOADS groups. The coupling was made using PROCAL’s body forces in RANS and the effective wake field was obtained by subtracting PROCAL’s propeller-induced

velocities from the RANS total velocities. The approach was then successfully used in 2013 to analyse the shaft loads from a VLCC in a manoeuvre for which both full RANS and full-scale data were available. For a cruise vessel, the influence of the shaft alignment on the wake field and propeller cavitation behaviour was studied in detail, making extensive use of RANS and PROCAL computations.

The structural response of the propeller to the hydrodynamic loading was analysed through the coupling of PROCAL and FEM packages. Additionally, the structural response of the hull due to propeller- induced hull-pressure fluctuations was studied, using the coupling between EXCALIBUR and FEM.

Ducted propulsors At the end of PROCAL 2 in 2009, there was a strong desire to extend PROCAL’s capabilities to ducted propellers. It was estimated that more than 50% of the propellers designed by manufacturers in CRS are to operate

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