Fluid Dynamics
Benefit from GL’s significant experience
GL has significant experience in the area of fluid dynamics. Since the early 1970’s, numerical methods have been employed to solve fluid dynamic problems and in the mid 1990’s GL was one of the first maritime companies to employ modern CFD methods (RANSE).
Our computational methods are constantly being developed and validated, often in close cooperation with software companies and universities. These activities are presented in many publications at international conferences and in journals. Unlike model tests, numerical methods give access to all flow variables and allow full-scale simulations. With GL’s knowledge and experience in fluid dynamics, we are able to offer our customers solutions to hydrodynamic problems in all technical areas. A selection of available services follows. These services can be offered for any type of vessel.
Seakeeping
- Dynamic stability of ships, including prediction of ship motions through to capsizing
- Performance-based safety assessment for ship designs
- Operational guidance, assisting the ship master in heavy weather
- Accelerations of ship and cargo for the dimensioning of lashing systems and to ensure the safety and comfort of passengers and crew
- Relative motions, e.g. for interim load line exemption certificates (ILLC) and for the definition of load spectra on appendages
Design Loads
- Sectional loads for hull girder dimensioning as an addition or alternative to rule-based loads
- Pressure distributions for FEA
- Envelop curves using long-term seaway statistics and the operational profile
- Elastic deformations and fluid-structure interaction due to whipping and springing can be taken into account.
Slamming, Sloshing and Green Water
The following loads acting on structures of ships and offshore units can be predicted:
- Sloshing for the dimensioning of tanks
- Slamming for the dimensioning of local structures
- Wave impacts for the dimensioning of wave breakers, superstructures, etc.
Hydrodynamic Loads Acting on Appendage
For the dimensioning of appendages, loads can be obtained from numerical simulations and
used as an addition or alternative to rules. Free-surface effects and cavitation behaviour can be
considered in the analysis. Applications include the following:
- Propellers, PODs, bow thrusters, etc.
- Rudders
- Flaps, fins, etc
Air Flows, Fire and Smoke Propagation
- Prediction of smoke propagation in order to prevent discomfort and harm to health
- Computation of wind forces for added resistance and manoeuvring simulations
- Calculation of air flow on top decks and helipads
- Simulation of fire development
Ventilation and Heat Transfer
Simulation of internal flows and heat transfer in ship compartments can be offered:
- Assessment of ventilation systems for the prevention of dangerous gas concentrations and high temperatures, e.g. for reefer cargo holds
- Prediction of temperature, velocity and pressure distributions for assessment of comfort
- Prediction of smoke propagation in order to prevent discomfort and harm to health
Offshore
All the services presented are equally applicable to offshore problems. For example, the following problems can be solved:
- Seaway loads for the definition of stability and dimensioning of structures
- Motions and accelerations during sea transport of offshore structures
- Mooring
Other Applications
Various other problems can be solved with numerical simulations, for example:
- Simulation ship encounters for collision risk assessment
- Manoeuvring
- Slamming Calculation of squat (dynamic trim and sinkage) of ships in restricted waterways
- Simulation of vortex shedding in order to assess vibrations and consequences for comfort
- Computation of towing forces
