Marine and offshore

Marine and offshore

G-MET Technologies is located in the heart of an industrial fabric rich in maritime and offshore activities. We use our calculation methodologies for solving various marine and offshore problems.

Nowadays CFD is a major tool for shipbuilding and design. The use of CFD for the shipbuilding industry is motivated by environmental considerations in improving the energy efficiency of marine vessels, safety analysis, or pure performance. Due to this context, the current applications in the industrial field like resistance calculation, self-propulsion, trim optimization studies, added resistance in waves, or bulbous bow design require intensive CPU resources and accurate simulation results.

At G-MET Technologies we mainly use OpenFOAM for our simulations in the marine and offshore industry. Because we want to propose the best solution for our client we have developed and qualified, an in-house solver dedicated to incompressible two-phase flow and called marineFoam

In addition, we also offer structural sizing studies, in particular for metallic equipment boarded on ships.

Main types of simulations that we perform for marine and offshore industry

marineFoam solver

We have developed a custom solver (marineFoam) based on OpenFOAM toolbox code for marine and naval applications. In comparison to the standard OpenFOAM two-phases flow solver (interFoam), marineFoam is more robust and produce accurate results even at large CFL number (~ 200) (for example for ship resistance assessment). This allows us to perform accurate simulations in a shorter time. 

Advanced numerical methods and physic

We coded and developed many features for increasing the stability and capabilities of the code


We have performed intensive CFD validation using international workshop CFD results: Gothenburg 2010, Tokyo 2015, or LLOYD 2016…

Our specialities


We use the Volume-of-Fluid method and algebraic schemes: HRIC, BICS, CICSAM...

6 DoF

We use a special 6 DoF formulation with Adams' Bashforth Moulton scheme and Atkins dynamic relaxation.

Ghost Fluid Method

We use the GFM for pressure and density discontinuities handling.

Actuator Disk Theory

We have implemented a special library for simulating actuator disk.

Waves Simulation

We have incorporated the waves2foam package of Niels Gjøl Jacobsen.

Ship resistance simulations

Ship resistance simulations allow us to obtain very relevant data while designing a hull such as its resistance, its dynamic behavior (pitch angle and vertical displacement), or the shape of the wave pattern.

In addition, our calculation methodologies allow us to offer simulation deadlines incredibly short. We are able to give our clients the results within a 24 to 48 hours deadline. Of course, we can work either with a full or model scale hull and even with a wide range of Froude’s numbers.

Structural design

The applications of structural design for the marine and offshore environment are numerous. It may involve studying the structural strength of a ship’s hull as illustrated in this video or equipment and appendages mounted on the ship. The usual mechanical loads are varied (accelerations, forces, moments, pressure) in static or dynamic (vibrations, response spectra, implicit or explicit transients in the case of shock or collision simulations). CFD can also be used to calculate input data (pressure fields, accelerations, mechanical torsorsors) useful for the mechanical engineer, especially when the design margins are small due to the use of overly pessimistic loads.

Propellers and thrusters

In the early stage of ship design, the determination of open-water propeller characteristics is mandatory. However, a full-scale propeller experiment can be complex. Thusly, CFD is an attractive tool for open-water propeller characteristics calculation. Indeed, choosing the right propeller design is very important because it has a direct impact on ship propulsion. To assess performance curves, the propeller is traditionally placed in an open-water tank at a fixed rotational rate where the advanced speed varies. Thrust coefficient, torque coefficient, and propeller open water analysis efficiency are by this way determined. These curves can be directly used to perform fast and accurate self-propulsion calculations.

Waves loads

Computational fluid dynamic (CFD) is a very powerful tool for evaluating wave loads.

This example illustrates a demonstration case of waves interacting with an offshore structure (jacket). The waves are generated with standard OpenFOAM library (stokes 5th order). The simulation is run with marineFoam solver using BICS scheme (Queuty et al). Pressure and density discontinuities are handled thanks to the Ghost Fluid Method. 

Furthermore, the calculated pressure fields can be used by the mechanics to evaluate forces and carry out structural sizing.

Ship resistance in head sea

Wave/currents simulations provide data on the increase in resistance in the presence of waves (generally between 10 and 40% compared to a situation in a calm sea). The example below, from the Tokyo 2015 Workshop, consists of comparing (hull with rudder) time evolution of force coefficient, heave, and pitch for the KCS at Froude = 0.261. For this case, the sea conditions are wavelength: 11.84 m, height: 0.196 m. Numerical simulations are carried out in transient with marineFoam. The waves2foam library makes it possible to generate stream function waves and the free surface is calculated with the modified CICSAM scheme (Wacławczyk). Pressure and density discontinuities are handled thanks to the Ghost Fluid Method. The ship movements (2DOF) are calculated using a predictor/corrector approach (Adams Bashforth Moulton).

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G-MET Technologies is a consulting firm specialized in numerical simulations applied to computational fluid dynamics (CFD), structural mechanics, and heat transfers​. In order to know more about us or to get in touch please visit our contact page or click on the button below.