Wave Added Resistance

By Patrick Hooijmans
Thursday, September 20, 2012

MARIN Unravels Secrets of Wave Added Resistance
 

Model tests for the evaluation of ship designs should not only be performed in calm water but also in waves. MARIN’s new Depressurized Wave Basin (DWB) helps unravel some of the mysteries of wave added resistance.
A ship is usually designed with a focus on its performance in calm water. However, operational conditions should be taken into account, including added resistance due to waves because it is an important factor in the economical performance of a ship.
The sustained speed in storm conditions should be investigated but also the power increase in typical service conditions. And with the trend for an increasing ship size, the latter becomes even more important. In addition, upcoming regulations such as EEDI require a very careful correction for the added resistance during speed trials.
Using large ship models in a 240x18x8 m towing tank can make the difference when trying to understand the secrets of wave added resistance. In the DWB a large ship model of a Very Large Container Ship of about 350 m for instance, can be tested at a model scale ratio of 1 to 30.
In our Seakeeping and Maneuvering Basin (SMB) the scale ratio typically doubles, which means that a 1.5 m wave for the ship would require a 2.5 cm wave in the SMB and a 5 cm wave in the DWB. This increase, in combination with increased measurement accuracy, improves the prediction of wave added resistance in typical service conditions.
A further benefit of the DWB is that only one large ship model is used to perform calm water resistance and propulsion tests, cavitation observations, hull pressure measurements and wave added resistance tests for mild to severe weather conditions. When well prepared, all the tests can be conducted within one week. A ship model can be chosen with large propeller models with a diameter of about 300mm, reducing significant scale effects on propeller blade cavitation and propeller thrust and torque. This provides a high level of accuracy when measuring for instance the wave added resistance. In this way MARIN expects to unveil some of the secrets of wave added resistance.

The Author
Patrick Hooijmans is project manager at the Ships department of MARIN, the Maritime Research Institute Netherlands. MARIN offers simulation, model testing, full-scale measurements and training programs, to the shipbuilding and offshore industry and governments.
Email: p.hooijmans@marin.nl

(As published in the August 2012 edition of Maritime Reporter - www.marinelink.com)

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

Technology

World's Largest Ship: Pioneering Spirit Awaits Completion

Final construction aboard the world’s largest vessel, Pioneering Spirit (formerly named Pieter Schelte), is wrapping up in the Port of Rotterdam before the vessel

Port St. John to Install KleinPort System

Klein Systems Group Ltd. announced today that it has entered into an agreement to install the KleinPort Port Management Information System at Port Saint John, New Brunswick.

ST Marine Celebrates Naming of Vessels

Singapore Technologies Marine Ltd (ST Marine), the marine arm of Singapore Technologies Engineering Ltd (ST Engineering), held the Naming Ceremony today for the second Patrol Vessel (PV),

Naval Architecture

All American Marine Delivers Ferry to Seattle

All American Marine, Inc. (AAM) today announced the delivery of a new passenger ferry that will serve the city of Seattle.    The vessel, MV Sally Fox, was dedicated

SCI takes Delivery of VLCC "Desh Vibhor"

The Shipping Corporation of India Ltd. (SCI) accepted delivery of a Very Large Crude Oil Carrier (VLCC) on 28 March, 2015. The vessel has been named “Desh Vibhor”.

VIKING LifeCraft Presented at IMO

This week, VIKING Life-Saving Equipment took a step towards gaining approval for the VIKING LifeCraft, its alternative life-saving appliance (LSA) for passenger ships.

 
 
Maritime Security Maritime Standards Naval Architecture Navigation Offshore Oil Pipelines Pod Propulsion Port Authority Shipbuilding / Vessel Construction Winch
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: 0.1667 sec (6 req/sec)