FSB University of Zagreb Fakulty of Mechanical Engineering and Naval Architecture Department of Energy, Power Engineering and Environment OpenFOAM for marine hydrodynamics CFD Vuko VUK ˇ CEVI ´ C Inno GATIN ABSTRACT This poster presents the capabili- ties of the OpenFOAM’s Naval Hy- dro pack for marine hydrodynamics CFD simulations developed within Prof. Jasak’s CFD group. The CFD model is used for accurate simulations regarding: Steady resistance with dynamic sinkage and trim, Seakeeping in head and oblique, regular and irregular sea states, Self propulsion with modelled and discretised propellers, Manoeuvring: – Turning circle, – Zig–zag tests, – Crabbing. Versatile, robust and efficient simu- lations are enabled with: Ghost–Fluid–Method: accurate treatment of discontinuities at the free surface, Interface capturing: Volume–of– Fluid or Level Set Method, Solution decomposition: calculat- ing perturbation around potential flow solution, Domain decomposition: prevent- ing wave reflection, Semi–monolithic approach: im- plicitly coupled pressure equation and rigid body equations. Steady resistance simulations Rapid steady resistance simulations are routinely performed to aid the design of ships in order to minimize fuel consumption. Image presents wave elevation for three different bow shapes, where the results have been obtained within twelve hours, including meshing, case set–up, simulations and post processing. Seakeeping simulations Fully non–linear CFD seakeeping simu- lations are becoming increasingly utilised because of their ability to accurately cal- culate added resistance of ship in waves. Reliable estimate of transfer function can be obtained within few days using a modest HPC workstation (64 CPUs). 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Dimensionless wave length, λ/L PP 0 5 10 15 20 25 30 Total resistance coefficient, C T · 10 3 Mean, navalFoam Mean, swenseFoam Mean, EXP First order, navalFoam First order, swenseFoam First order, EXP C1 C2 C3 C4 C5 Oblique wave simulations with roll motion and forward speed do not represent a diffi- culty as opposed to potential flow methods. Full scale self–propulsion One of the main benefits of CFD is its ability to calculate full scale flows without the need for error prone extrapolation of results. The Naval Hydro pack has been recently used to calculate the self–propulsion point for a 138 meters long general cargo carrier with constant propeller revolution rate. 0 100 200 300 400 500 600 700 800 Time, s 11.8 12 12.2 12.4 12.6 12.8 13 13.2 13.4 13.6 13.8 14 Forward speed, kn navalFoam, 7M mesh navalFoam, 11M mesh Sea trial, measured speed on 1st run Sea trial, measured speed on 2nd run ISO 15016 speed Reference for sea trial measurements and results: Dmitriy Ponkratov, Lloyd’s Register: Workshop on Ship Scale Hydrodynamic Computer Simulation, November 2016 Manoeuvring: turning circle Actuator disk model allows fast CFD simu- lations of different manoeuvres. Using the actuator disk model and deflected rudder, tactical diameter of the KVLCC model has been calculated. Conclusion With increasing availability of computational resources, CFD for marine hydrodynamics is gaining in popularity and slowly replacing traditional methods: experiments and poten- tial flow based numerical methods. Acknowledgements We are grateful for our industrial sponsors: Hyundai Heavy Industries and Bureau Ver- itas for supporting the development of the Naval Hydro pack. 8th Floor CFD@FSB Zagreb, 2017 Supervisor: Prof. Hrvoje Jasak www.fsb.hr/cfd Feel free to contact us at [email protected] and [email protected], or take a look at our YouTube channel: 8th Floor CFD@FSB.