CFD Simulation ships

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Ship resistance & powering prediction

During the different stages of the ship design, the use of advanced CFD tools allow VICUSdt to determine the resistance of the ship accurately, in still water or on any sea state, for bare hull or a complete hull with appendages. A correct powering prediction is the first step in a successful ship project. We carry out accurate ship powering prediction for leading engineering offices and shipyards worldwide.

Hull form optimization

Improving the hull form design for minimum ship resistance in the different ship operational conditions, from planning craft to large container vessels. We have a multi-objective optimization methodology which together with our skilled naval architects will guarantee the performance of your hull for every sea state. The optimization covers not only the bow but also the ship aft body ensuring a good wake field.

For existing vessels we can provide new and optimized designs for bulbous bow or complete fore body, based on the real performance from our monitoring or ship owner records, the design is tailor-made for the ship’s real operational profile, ensuring the best return of investment.

Wake calculations & appendage alignment

The calculation and assessment of the flow arriving to the propeller is critical for a successful propeller design. A perfect knowledge of the nominal and effective wake allows a more adjusted propeller design, minimizing cavitation and increasing efficiency, resulting in significant fuel savings.

Appendages should be aligned with the streamlines in order to minimize resistance and reduce turbulence. When we refer to oceanographic and seismic research vessels, appendage alignment is a critical issue, especially for the gondola where the main acoustic sensors are located. In this type of installations we need to design and locate the gondola below the hull so it is free from air bubble sweep down from the free surface. An improperly designed or located gondola in any of these ship types can result in a very expensive but totally inefficient vessel, so don’t make mistakes and rely on the professionals for this issue. VICUSdt has participated in the hydrodynamic design of the most advanced oceanographic and seismic research vessels in recent years, complying with the underwater radiated noise regulation described in ICES 209.

Self-propulsion& bollard pull analysis

We have a fully validated methodology for carrying out numerical self propulsion tests with our CFD codes. Our experience in ship propellers and feedback from sea trials allow us to perform detailed predictions of the self-propulsion performance of any type of ship, determining effective wake coefficients, thrust deduction, rotary-relative efficiency and overall propulsion performance in behind conditions. The numerical self-propulsion simulation recreates the ship sailing with its designed propeller in such a way that the performance expected on its real life can be predicted with very high accuracy. The assessment of the thrust deduction factor is important for a redesign of the hull and modifications in the propulsion arrangement in such a way that the hull-propeller interaction is improved.

When it comes to bollard pull prediction, we have also validated our simulations with real tests performed on pusher boats, tugs and AHT. Don’t play with the bollard pull performance of your ship, count on us during the project stage and avoid costly problems discovered during sea trials.

Trim optimization analysis

Merchant vessels can achieve significant savings with the correct trim for each displacement and speed. To do so, the crew must know beforehand how to load the ship depending on the expected speed and loading condition, in order to minimize ballast loading. VICUSdt carry out routine trim optimization calculations for merchant vessels, from small LPG to some of the largest container vessels in the world.

Seakeeping

Ships operate in real sea state, not always in still water conditions, therefore it is essential for the ship hull to be designed to deal with incoming waves from every direction. The typical calculations we perform include:

  • RAO’s: response amplitude operators.
  • Accelerations for six degrees of freedom in any point of the vessel.
  • hip behaviour in the vicinity of an offshore structure (wind mill, platform…)
  • Bilge keel design and damping analysis
  • Parametric rolling

Manoeuvring & dynamic position analysis.

We have our own manoeuvring and dynamic positioning simulator. This tool is continuously upgraded with new data from CFD, towing tank and sea trials. The main services provided are:

  • DP capability plot
  • Crabbing speed
  • Turning circle
  • Crash stop
  • Zig zag
  • Course stability

Added resistance due to waves

The increase of ship resistance due to waves is calculated by means of CFD in order to evaluate the amount of additional power required for sailing at a certain speed compared to the still water case. With this information the sea margin can be evaluated based on a realistic assumption and taking into account the seas where is going to sail. The added resistance due to waves is one of the merit figures taken into account when we optimize the hull. VICUSdt can provide sets of data for a ship sailing at different speeds, drafts and courses for each sea state, with this information you can set up the weather routing system. This is typically done on merchant vessels receiving the weather forecast for the route they will follow.

Furthermore, the calculated forces and moments are typically used on offshore vessels to feed the Dynamic Positioning simulator for more accurate results.

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