A Zonal CFD Approach for Fully Nonlinear Simulations of Two Vessels in Launch and Recovery Operations

Lead Research Organisation: University of Plymouth
Department Name: Sch of Engineering

Abstract

Launch and recovery of small vehicles from a large vessel is a common operation in maritime sectors, such as launching and recovering unmanned underwater vehicles from a patrol of research vessel or launching and recovering lifeboats from offshore platforms or ships. Such operations are often performed in harsh sea conditions. The recent User Inspired Academic Challenge Workshop on Maritime Launch and Recovery, held in July 2014 and coordinated by BAE systems, identified various challenges associated with safe launch and recovery of off-board, surface and sub-surface assets from vessels while underway in severe sea conditions. One of them is the lack of an accurate and efficient modelling tool for predicting the hydrodynamic loads on and the motion of two floating bodies, such as vessels of different size which may be coupled by a non-rigid link, in close proximity in harsh seas. Such a tool may be employed to minimise the risk of collisions and unacceptable motions, and to facilitate early testing of new concepts and systems. It may also be used to estimate hydrodynamic loads during the deployment of a smaller vessel (for example, a lifeboat) and during recovery of a smaller vessel from the deck of a larger vessel. The difficulties associated with development of such tools lie in the following aspects: (1) the water waves in harsh sea states have to be simulated; (2) the motion of the small vehicle and change in its wetted surface during launch or recovery can be very large, possibly moving from totally dry in air to becoming entirely submerged; (3) the viscous effects may play an important role and cannot be ignored, and will affect the coupling between ocean waves and motion of the vehicles. Existing methods and tools available to the industry cannot deal with all of these issues together and typically require very high computational resources.

This project will develop an accurate and efficient numerical model that can be applied routinely for the analysis of the motion and loadings of two bodies in close proximity with or without physical connection in high sea-states, which of course can be employed to analyse the launch and recovery process of a small vehicle from a large vessel and to calculate the hydrodynamics during the process. This will be achieved building upon the recent developed numerical methods and computer codes by the project partners and also the success of the past and ongoing collaborative work between them. In addition, the project will involve several industrial partners to ensure the delivery of the project and to promote impact.

Planned Impact

This industry inspired and initiated project will address one of the key challenges faced for the certification of safe launch and recovery of assets from maritime platforms while underway in severe sea conditions by developing an accurate and fast prediction tool for the motion of two bodies of different sizes in close proximity in high sea-states. Such a tool is essential to identify and reduce the risks of collision and unacceptable motions during those operations (civil or military) hence the safety of personnel and asset integrity. It is also needed for early testing of new concepts and systems for marine launch and recovery operations to identify suitability and safety issues. Scientifically, an accurate and efficient modelling of the flow problem involving violent motion of water waves and its interaction with two floating bodies in relative and potentially arbitrary motions remains challenging, and to achieve this a number of novel CFD techniques have been proposed and will be implemented during the project as outlined in the Case for Support section of the proposal.
Direct beneficiaries of the developed integrated CFD tool and the new wave tank test data sets will be engineering companies/consultancy bodies and Classification Societies involved in the design and testing of new marine launch and recovery systems and both civil and military units involved in such operations. The new CFD techniques and associated HPC implementations will also benefit the general CFD community as a whole (other researchers in academia or commercial organisations working in any area involving free surface flows, more generally within CFD and related areas of computational physics).
To ensure the maximum impact of the project a number of routes for its dissemination have been identified and further details are given in the Pathways to impact document:
1. Direct engagement with project partners
2. Engagement with other projects within the Launch and Recovery inspired research
3. Contact with end users and wider scientific community through a dedicated website/wiki and social media
4. Training in the use of model and public engagement through joint workshops with CCP-WSI
5. Scientific and technical conferences
6. Journal publications
 
Description Physical wave tank experiments designed for launch and recovery and vessel vessel interactions.
Offshore supply vessel used as the large vessel and lifeboat for the small vessel.
Models (1:20 scale) constructed and experiments designed for June 2017.
A new set of experiments has been carried out to investigate vessel-vessel interaction of a large and small vessel at different spacings under different wave conditions, wave directions and with the vessels fixed and free to move in heave and pitch. Experiments have also been conducted to investigate wave structure interaction with a flexible structure.
Results are currently being analysed and publications are under development.
The datasets will become useful for other researchers to use for validation. New code developments were also presented for the simulation of wave structure interaction of flexible structures; overset methods for large body motions; coupling of two different solver types within the fluid domain; absorbing wave boundary conditions. The new code developments will be useful to others in academia and industry for numerical modelling of wave structure interaction.
Experiment data and the hydrodynamics of the vessel-vessel interactions and wave-vessel interactions have been analysed and presented in research papers in Applied Ocean Research and Ocean Engineering (under review). A linearised numerical model has been developed for comparison with the experiments and further comparisons are planned with co-Investigators using zonal-CFD approaches.
Exploitation Route Detailed information from experiments of vessel vessel interaction.
Validation data provided for numerical simulations.
The datasets will become useful for other researchers to use for validation. New code developments were also presented for the simulation of wave structure interaction of flexible structures; overset methods for large body motions; coupling of two different solver types within the fluid domain; absorbing wave boundary conditions. The new code developments will be useful to others in academia and industry for numerical modelling of wave structure interaction.
Sectors Aerospace, Defence and Marine

URL https://collaborate.plymouth.ac.uk/sites/cerg/Pages/LRProj_Home.aspx
 
Description The findings from the Zonal CFD project have been presented and discussed at two industry workshops: the first with the Society for Underwater Technology Group for Environmental Forces (SUT-GEF) meeting on Thursday 26/1/2017 at City University, London and the second combined with the SUT-GEF meeting on Thursday 25/1/2018 at City University, London, and then again final results were presented at the SUT-GEF meeting at City University in January 2019.
First Year Of Impact 2017
Sector Aerospace, Defence and Marine,Energy,Environment,Transport
Impact Types Economic

 
Description Extreme Loading on FOWT under Complex Environmental Conditions
Amount £332,158 (GBP)
Funding ID EP/T00424X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2020 
End 03/2023
 
Description Extreme Loading on Floating Offshore Wind Turbines (FOWTs) under Complex Environmental Conditions
Amount £44,275 (GBP)
Funding ID EP/T004274/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2020 
End 03/2023
 
Description Extreme Loading on Floating Offshore Wind Turbines (FOWTs) under Complex Environmental Conditions
Amount £63,391 (GBP)
Funding ID EP/T004339/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2019 
End 11/2022
 
Description Extreme Loading on Floating Offshore Wind Turbines (FOWTs) under Complex Environmental Conditions
Amount £389,691 (GBP)
Funding ID EP/T004177/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 03/2020 
End 03/2023
 
Description BAE Systems 
Organisation BAE Systems
Country United Kingdom 
Sector Academic/University 
PI Contribution Research collaboration
Collaborator Contribution member of Industry Advisory Board; attendance at project meetings
Impact review of project proposal; advice at project progress meetings
Start Year 2015
 
Description ESI Group 
Organisation ESI Group
Country France 
Sector Private 
PI Contribution Research collaboration; development of software and experiments.
Collaborator Contribution Member of industry Advisory Board, provision of software licences
Impact review of research proposal; attendance at project progress meetings and discussion
Start Year 2015
 
Description RNLI 
Organisation Royal National Lifeboat Institution
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Industry Advisory Board member for Zonal CFD project, EP/N008847
Collaborator Contribution Industry Advisory Board member for Zonal CFD project, EP/N008847
Impact Advisory Board member, assisted with proposal preparation and attends research progress meetings.
Start Year 2015
 
Description Veldman Groningen 
Organisation University of Groningen
Country Netherlands 
Sector Academic/University 
PI Contribution Experimental data set for wave structure interaction experiments; numerical tools for hydroelastic analysis; application of CFD to wave structure interaction and offshore wave impact.
Collaborator Contribution Contribution to research discussions; contributions to Project Steering Group.
Impact Research publications.
Start Year 2012
 
Description Zenotech 
Organisation Zenotech
Country United Kingdom 
Sector Private 
PI Contribution research collaboration
Collaborator Contribution staff time and travel to attend project progress meetings and join the project Industry Advisory Board
Impact review of proposal; contribution to project progress meetings
Start Year 2015
 
Description project industry advisory Board Member SEA ltd 
Organisation Systems Engineering & Assessment Ltd
Country United Kingdom 
Sector Private 
PI Contribution Collaborative research project
Collaborator Contribution Member of the project Industry Advisory Board, attend project meetings and help steer research
Impact Review project proposal; attend project progress meetings
Start Year 2015
 
Description Project meeting with Industry Partners 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Research Meeting with industry partners; discuss project results and their significance to the issue of autonomous control of vessels n launch and recovery operations. Discussion of potential follow on projects..
Year(s) Of Engagement Activity 2018
 
Description SUT GEF Meeting Jan 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Project meeting and SUT GEF (Society of Underwater Technologies Group for Environmental Forces) Industry Workshop at City University 26 January 2017
Year(s) Of Engagement Activity 2017
 
Description SUT-GEF meeting on Thursday 25/1/2018 at City University, London 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The findings from the Zonal CFD project were presented at the Society for Underwater Technology Group for Environmental Forces (SUT-GEF) meeting on Thursday 25/1/2018 at City University, London. An audience of approximately 30 industry and academic members attended and participated in the event.
Year(s) Of Engagement Activity 2018
 
Description SUTGEF Meeting at City University 17/01/2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Project results were presented at the Society for Underwater Technology Group for Environmental Forces meeting at City University in January 2019.
Year(s) Of Engagement Activity 2019