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Maritime

G-MET Ingénierie is located at the heart of an industrial fabric rich in maritime and offshore activities. We use our expertise in mechanical modelling and CFD simulation to solve a range of problems typically encountered in this sector.

Our main maritime customers

Today, CFD is a major tool for ship construction and design. The use of CFD in the shipbuilding industry is motivated in particular by environmental considerations (energy efficiency), certain safety aspects and pure performance.

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Advanced simulation for maritime and offshore engineering

Industrial applications such as strength calculations, self-propulsion, attitude optimisation studies, added strength or bulb design require intensive calculation resources and accurate simulation results.

At G-MET Ingénierie, we mainly use OpenFOAM for our CFD simulations in the marine and offshore industry. Because we want to offer the best solution for our customers, we have developed and qualified, in-house, a suite of tools dedicated to incompressible two-phase flows, with our solvers marineFoam and LSFoam.

We also offer structural design studies, in particular for metal equipment on board ships, or to calculate the mechanical strength of underwater drones (ROVs, AUVs) and their lifting and gripping systems.

Plan your study

Ship resistance simulations

Ship strength simulations allow us to obtain highly relevant data when designing a hull. For example, its strength, its dynamic behaviour (pitch angle and vertical displacement), or the shape of the wave pattern.

What's more, our calculation methodologies enable us to offer very short simulation timescales. We can provide our customers with the results within 24 to 48 hours. Of course, we can work with either a large-scale hull or a mock-up, and for a wide range of Froude numbers.

Structural sizing

There are many applications for structural design in the maritime and offshore environment. For example, the structural strength of a ship's hull can be studied, as shown in this video, or the structural strength of equipment and appendages mounted on the ship. The usual mechanical loads are varied (accelerations, forces, moments, pressure), both static and 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) that are useful for the mechanical computer, particularly when the design margins are small due to the use of overly pessimistic loads.

Propellers and thrusters

Full-scale propeller testing can be complex. CFD is an attractive tool for calculating propeller characteristics in open water. Choosing the right propeller design is crucial, as it has a direct impact on the propulsive performance of the vessel (or underwater craft). In addition, to evaluate performance curves, the propeller is traditionally placed in a tank at a fixed rotation speed, and then different speeds of advance are tested. In this way, the thrust coefficient, torque coefficient and efficiency can be determined from the open-water calculations. These curves can be used directly to perform self-propulsion calculations by feeding the propeller disc model.

Wave propagation

Computational fluid dynamics (CFD) is a very powerful tool for assessing wave loads and impacts. In addition, the calculated pressure fields can be used by mechanics to assess forces and carry out structural dimensioning.

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

Added resistance under swell

Resistance simulations with waves provide data on the increase in resistance in the presence of waves (order of magnitude: 10 to 40% compared with a situation in calm seas). The example on the right, taken from the Tokyo 2015 workshop, consists of comparing the time evolution (hull with rudder) of the force coefficient, sinkage and trim for the KCS at Froude = 0.261. In 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 is used to generate stream functions and the free surface is calculated with the modified CICSAM scheme (Wacławczyk). Pressure and density discontinuities are handled using the Ghost Fluid method. Vessel motions (2DOF) are computed using a predictor / corrector approach (Adams Bashforth Moulton).

Marine structural calculations

G-MET works in the maritime sector to carry out structural calculations on on-board or submerged equipment. In particular, we deal with equipment support frames, as well as handling structures for ROVs (Remotely Operated Vehicles) and AUVs (Autonomous Underwater Vehicles).

We also analyse the mechanical strength of the ROVs and AUVs themselves, which are subjected to complex loads: hydrostatic pressures, dynamic forces, vibrations and shock calculations.

Depending on the case, our studies incorporate non-linear phenomena (large displacements, friction, contact) to faithfully reproduce the actual behaviour of structures in demanding marine environments.

Ship resistance simulations

Ship strength simulations allow us to obtain highly relevant data when designing a hull. For example, its strength, its dynamic behaviour (pitch angle and vertical displacement), or the shape of the wave pattern.

What's more, our calculation methodologies enable us to offer very short simulation timescales. We can provide our customers with the results within 24 to 48 hours. Of course, we can work with either a large-scale hull or a mock-up, and for a wide range of Froude numbers.

Ship resistance simulations

Ship strength simulations allow us to obtain highly relevant data when designing a hull. For example, its strength, its dynamic behaviour (pitch angle and vertical displacement), or the shape of the wave pattern.

What's more, our calculation methodologies enable us to offer very short simulation timescales. We can provide our customers with the results within 24 to 48 hours. Of course, we can work with either a large-scale hull or a mock-up, and for a wide range of Froude numbers.

Structural sizing

There are many applications for structural design in the maritime and offshore environment. For example, the structural strength of a ship's hull can be studied, as shown in this video, or the structural strength of equipment and appendages mounted on the ship. The usual mechanical loads are varied (accelerations, forces, moments, pressure), both static and 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) that are useful for the mechanical computer, particularly when the design margins are small due to the use of overly pessimistic loads.

Propellers and thrusters

Full-scale propeller testing can be complex. CFD is an attractive tool for calculating propeller characteristics in open water. Choosing the right propeller design is crucial, as it has a direct impact on the propulsive performance of the vessel (or underwater craft). In addition, to evaluate performance curves, the propeller is traditionally placed in a tank at a fixed rotation speed, and then different speeds of advance are tested. In this way, the thrust coefficient, torque coefficient and efficiency can be determined from the open-water calculations. These curves can be used directly to perform self-propulsion calculations by feeding the propeller disc model.

Wave propagation

Computational fluid dynamics (CFD) is a very powerful tool for assessing wave loads and impacts. In addition, the calculated pressure fields can be used by mechanics to assess forces and carry out structural dimensioning.

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

Added resistance under swell

Resistance simulations with waves provide data on the increase in resistance in the presence of waves (order of magnitude: 10 to 40% compared with a situation in calm seas). The example on the right, taken from the Tokyo 2015 workshop, consists of comparing the time evolution (hull with rudder) of the force coefficient, sinkage and trim for the KCS at Froude = 0.261. In 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 is used to generate stream functions and the free surface is calculated with the modified CICSAM scheme (Wacławczyk). Pressure and density discontinuities are handled using the Ghost Fluid method. Vessel motions (2DOF) are computed using a predictor / corrector approach (Adams Bashforth Moulton).

Taking to the open seas set

Need support for your naval or offshore projects? Talk to our experts to design high-performance, reliable solutions tailored to your maritime environment.