HELYX-Marine is an extension module for HELYX developed by ENGYS in conjunction with Prof. Kevin Maki of the Department of Naval Architecture and Marine Engineering of the University of Michigan. The module incorporates a comprehensive set of CFD solvers and simulation tools to cover the main aspects of ship hydrodynamics and design optimisation of naval and maritime applications.

HELYX-Marine has been validated across various cases and has proven successful in both industrial and research projects, including the JoRes project which focuses on enhancing the accuracy and reliability of CFD software tools for full-scale ship hydrodynamics. To streamline the process, HELYX-Marine supports a set of automated workflows to facilitate the automatic creation of the computational grid and setup of the CFD model. They operate based on geometry and conditions, following best practices that have been validated and verified over a span of more than 10 years.


Calm Water Resistance

Whether your interest lies in model scale or full-scale resistance tests, HELYX-Marine offers an accurate non-linear RANS Volume-Of-Fluid (VOF) solver predicting calm water behaviour. To ensure an accurate prediction of forces, hull motion, fully resolved wave patterns on the hull, and free surface elevation in operating conditions, we employ an efficient Adaptive Mesh Refinement (AMR) method. This method is coupled with a 6 Degrees of Freedom (DoF) rigid-body motion library to account for sinkage, and trim. In addition to the VOF solver, HELYX-Marine provides a linearized free-surface solver for calculating calm water resistance. This method combines the RANS viscous flow solution near the hull with a specialized boundary condition to model free-surface elevation. It is suitable for low Froude numbers and slender body hulls, and due its fast turnaround times with respect to the VOF solver it is ideal for automated hull form optimisation using parametric surface morphing.

Free-surface elevation for the GPPH* hull form – Experiments (left) and CFD (right), *Image taken from Evan Lee at al., Experimental Results for the Calm Water Resistance of the Generic Prismatic Planing Hull (GPPH). Report NSWCCD-80-TR-2017/015, Naval Surface Warfare Center Carderock Division, 2017


The following features are included as standard with the HELYX-Marine add-on module:

  • 6 DoF VOF solver: for calm water resistance and seakeeping analysis including 6 DoF ship motion.
  • Linearized free-surface solver: for calm water ship hull resistance prediction applied to slender body hulls and low Froude numbers.
  • Self-propulsion models: for simulating both actual propellers and body-force models via dedicated controllers.
  • Regular and irregular waves models: for realistic seakeeping conditions.
  • Fully supported in HELYX-GUI: for simplified ease-of-use.

 

Seakeeping Analysis

HELYX-Marine features an advanced seakeeping designed for simulating the motion of a body on or near the air-water interface. It solves the six-degree-of-freedom equations of motion and is suitable for a wide range of problems, including the free-fall of a body that impacts the air-water interface, for the seakeeping response of a surface vessel or submarine, or for the manoeuvring response of a ship. A set of regular and irregular wave generation libraries is provided and an efficient implicit relaxation zone implementation to tackle the most difficult problems such as water impact,breaking waves and waves reflection. The solver is coupled with an AMR library to ensure accurate resolution of dynamically changing free-surface patterns

Seakeeping simulation of the ONR Tumblehome ship showing free-surface elevation.

Self-propulsion

To address the hull-propeller interaction, HELYX-Marine provides an advanced solver for self-propulsion modelling. Users can choose to model the actual discretised propeller using a precise sliding mesh approach or opt for an efficient body-force actuator disk model to replicate conditions resembling propulsion test models or full-scale scenarios as an alternative to sea trials. To achieve realistic test conditions, the software includes an efficient PID controller. This controller allows users to adjust the propeller revolution speed to match either a target cruising speed or a skin friction correction force.

Self-propulsion simulation of the MV regal bulk carrier showing the flow pattern around the propeller and the free surface elevation.

References

B. di Paolo, S. J. Wong, P. Geremia and K. J. Maki, “Computation of Ship Manoeuvring in Irregular Waves with CFD”, X International Conference on Computational Methods in Marine Engineering, 27-29 June, 2023

P. Geremia, K. J. Maki, D. Deising, “A new Free-Surface Adaptive Grid Refinement Method for Marine Applications”, The 16th OpenFOAM Workshop (OFW16), 7-11 June 2021, Dublin, Ireland, 2021

P. Geremia, K. J. Maki, and P. Alexias, “A Linearized Free-Surface RANS Method for Ship Maneuvering”, VIII International Conference on Computational Methods in Marine Engineering, 13-15 May, 2019

 

Want to Buy?

The utilities and solvers in HELYX-Marine are released under the GNU General Public License for the benefit of the end-user. For further information about HELYX-Marine features, availability and prices, please contact us today or speak to one of our local sales representatives.

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