CFD


CFD
Computational Fluid Dynamics

CFD refers to the field of numerical computation of viscous flows. MARIN uses CFD on a large scale in practical projects, and has been one of the first to do this: Already from around 1995 the PARNASSOS code has been used successfully in consultancy. Today, our CFD work solves many design questions, provides many full-scale predictions, and indicates physical effects that in the past could just be crudely approximated.

MARIN’s CFD use in consultancy is unique in several regards:

  • Integration of the use of computations with dedicated experiments and with an extensive knowhow of the physics and design issues.
  • Careful and extensive analysis of computed flow, and comparison with known design trends.
  • Use of in-house flow codes dedicated to the ship and offshore hydrodynamic field, developed by MARIN specialists in close communication with those applying the methods in practice.
  • Availability of up-to-date High-Performance Computing clusters (2000 computing cores in total) permitting detailed flow computations without compromise on accuracy.
  • An acknowledged track record in quantification of computational accuracy and uncertainty, and a CFD philosophy based on the insights thus collected.
Application fields
The CFD tools play an increasingly important role in MARIN’s services to the industry; permitting a more detailed analysis and design, providing a clear diagnosis of problems, giving insight in scale effects, predicting full-scale forces, etc. As at MARIN the CFD use is fully integrated in the industrial consultancy work, for inquiries please address the relevant Business Unit.

CFD for Ships can be used for a wide variety of applications: from consultancy in an early design stage to high-end calculations in order to accurately determine the ship’s performance. For the evaluation and improvement of hull flow quality CFD is used for quite some years to understand the flow physics and improve the MARIN ship designs. These calculations can also be used to do appendage alignment, wave pattern prediction, and in case of model testing: prediction of scale effects on resistance and wake field. With efficient hull deformation tools linking with the CFD-tools hull form optimisation studies can be automated and hull designs even further improved. The coupling with an inviscid propeller code permits efficient full-scale power prediction. However, also full RANS calculations are possible for the analysis of propulsors, ships with Energy-Saving Devices and ship propulsor interaction. Other fields of application go towards submarines, and ship manoeuvring and more fields will follow shortly.
For more information, please contact Business Unit Ships (ships@marin.nl)

CFD for Offshore encompasses a large variety of complicated flow problems. Forces on offshore structures in current, wind forces, and thruster interaction problems are examples for which CFD already plays a role in industrial service. Further developments are aimed at being able to calculate free-surface flows and moving objects. For moving objects the coupling of the flow solution with forced and free object motions is currently being implemented.
For more information, please contact Business Unit Offshore (offshore@marin.nl)

Tools used
Two main CFD tools are being used:

PARNASSOS is a dedicated code for computing the steady flow around ship hulls. It is used extensively in practical projects ( > 100 computations / year for customers).

ReFRESCO is a more general code, applicable to steady or unsteady flows and complicated geometries. Simultaneous with a further development of additional features, the method is used in practical projects and Joint-Industry research projects.

Software Sales
Some software tools are available for commercial use outside MARIN. A complete overview of these software tools for sale can be found under Software Sales.

Contact
For more information on CFD, please contact the R&D department.

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