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 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Technology

Google Maps Goes Coastal with Unmanned Boat

A new high-tech unmanned vessel, launched with the help of Google, will use innovative technologies from the boatbuilding and mapping fields to map shorelines and

Bollinger Delivers 14th FRC to USCG

Bollinger Shipyards has delivered the 14th Fast Response Cutter (FRC), Heriberto Hernandez, to the United States Coast Guard (USCG). The 154-foot patrol craft

Korean Registry Okays Transas ECDIS

Transas, one of the world's leading providers of integrated navigation solutions, received ECDIS type-approval from the Korean Registry (Korea Marine Equipment Research Institute),

Offshore

Activists Block Shell's Arctic Drilling Quest

Greenpeace protestors dangling from a bridge on Thursday in Portland, Oregon, halted an icebreaker that Royal Dutch Shell needs in northern Alaska before it can

MOL Wins Eco Awards in California

Mitsui O.S.K. Lines, Ltd. earned recognition from the ports of both Los Angeles and Long Beach, California, today, for its efforts to ensure compliance with

Mexico to Postpone Deep Water Auction

Mexico, which has started to open its nationalized oil industry to additional private investment, will postpone auctions for deep-water oil exploration and production

Energy

Shell Moves Ahead in Arctic with Exploratory Well

Shell Oil's controversial icebreaker MSV Fennica weaved through nine remaining protesters hanging from the St. Johns Bridge and made its way toward the Pacific Ocean.

US Senate Energy Panel Votes to Lift Oil Export Ban

The U.S. Senate Energy Committee on Thursday passed a bill that would lift a decades-old ban on the export of crude oil.   The 22-member panel passed the bill

Activists Block Shell's Arctic Drilling Quest

Greenpeace protestors dangling from a bridge on Thursday in Portland, Oregon, halted an icebreaker that Royal Dutch Shell needs in northern Alaska before it can

 
 
Maritime Careers / Shipboard Positions Maritime Security Maritime Standards Navigation Offshore Oil Pipelines Salvage Ship Electronics Ship Simulators Winch
rss | archive | history | articles | privacy | 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: 0.1527 sec (7 req/sec)