Testing Breaking Waves vs. Offshore Wind Turbines

Tuesday, November 16, 2010

More than 60 representatives of the international offshore wind industry gathered last week at the Offshore Wind Seminar, organized by the Maritime Research Institute Netherlands (MARIN) and the Energy research Centre of the Netherlands (ECN). This seminar included a visit to unique model tests in the MARIN facilities of breaking waves against an offshore wind turbine. This pilot series of model tests, with a special model of an offshore wind turbine with realistic flexibility, was completed and confirmed that breaking waves can induced significant oscillations and accelerations in the turbine.

Dr. Bas Buchner, Vice President of MARIN and leader of its Renewable ENergy Team (RENT), said, “MARIN wants to contribute to the development of reliable offshore renewable energy with this expertise from the maritime industry. Breaking waves can occur quite often in the shallow water areas of fixed wind turbines. Considering the relatively flexible foundations and towers of offshore wind turbines, we realized that the impulsive loading of breaking waves might result in resonant vibrations of the structure. This can have significant effects on the loads in the tower and accelerations in the critical mechanical systems at nacelle level . But we did not want to state this as a problem without a confirmation, so we developed these pilot model tests within our own R&D.”

For this purpose a special model was developed by MARIN’s specialists in the field of hydrodynamic loading and structural response. The model material and set-up was chosen such that the model had the correct flexibility and natural periods, a technique recently developed to investigate the vibrations of ships in extreme waves.

The initial results of the tests confirm that the tower can vibrate due to the breaking waves. Erik-Jan de Ridder, the responsible MARIN Project Manager, said, “When a large wave hit the foundation and tower, the tower started to vibrate at its natural periods. At nacelle level this resulted in large horizontal accelerations, in one case even up to 0.5g (5m/s2). Although these results need further analysis, the first observation is that these values are large and will impact the design and operation of the turbine.”

The test results will now be further analyzed together with MARIN’s partner ECN based on its extensive expertise in turbine design, mechanics and dynamics. Aart van der Pal, Manager Integral Wind Turbine Design of ECN, said, “Breaking wave loads can affect the extreme and fatigue loads on the foundation, tower, turbine blades, shaft, gearbox and generator, aspects that have not been studied in detail so far. This will need to be taken into account in the design process.”

Together with a number of other partners, MARIN and ECN are in the process of starting up a Joint Industry Project (JIP) with the acronym ‘WiFi’: Wave impacts on Fixed turbines. As independent institute in the Offshore and Shipping industry, MARIN has a lot of experience in leading JIPs. The objective of the WiFi JIP is to develop a design methodology for offshore wind turbines that includes the effect of steep and breaking waves.

 

Maritime Reporter July 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Technology

TMT CEO Files $100m IP Suit Over Vessel Sale

Hsin-Chi Su, Chairman and CEO of Today Makes Tomorrow Group (TMT) launched a suit in Texas federal court on July 28, 2014, alleging that a planned bankruptcy sale of three company ships, including M.

MN 100: Dometic Marine

2000 N. Andrews Ave. Ext. Pompano Beach, Florida 33069 Tel: (954) 973-2477    Email: ned.trigg@dometic.com Website: www.dometic.com CEO: Roger Johansson President:

Harris Secures Certification for its Multi-channel Manpack Radio

Harris Corporation (NYSE:HRS) has received Type-1 National Security Agency (NSA) certification for its Falcon III® RF-340M multi-channel manpack radio. The certification

Offshore

Scotland Site for World's Biggest Tidal Array

The world’s biggest tidal array is to be built in North Scotland bringing jobs and energy security to the Pentland Firth region, informs a UK Government news release.

CBP Aircraft Locates Vessel in Distress

U.S. Customs and Border Protection Office of Air and Marine agents assigned to the North Dakota Air Branch have located four people on Red Lake after a call

EMGS Reports 2Q and 1H 2014 Results

Electromagnetic Geoservices ASA's (EMGS) reported revenues of USD 42.5 million in the second quarter 2014, down from USD 61.3 million in the first quarter this year and from USD 44.

Energy

Chilean Court Rejects Appeal Against Crow River Project

Chile's Supreme Court on Thursday rejected an application for an environmental organization against Crow River hydroelectric project, which plans to build in the

EMGS Reports 2Q and 1H 2014 Results

Electromagnetic Geoservices ASA's (EMGS) reported revenues of USD 42.5 million in the second quarter 2014, down from USD 61.3 million in the first quarter this year and from USD 44.

Banking on US Shale Gas Boom, Asia Petrochemical Firms Switch to LPG

Asia petrochemicals firms are building tanks and retooling plants to store and process liquefied petroleum gas imported from the United States, counting on a flood

 
 
Maritime Careers / Shipboard Positions Naval Architecture Navigation Pipelines Pod Propulsion Salvage Ship Electronics Ship Repair Ship Simulators Shipbuilding / Vessel Construction
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1160 sec (9 req/sec)