MARIN will be presenting a paper on "Decreasing frictional resistance by air lubrication" at the 20th HISWA Symposium, 17 & 18 November 2008, in Amsterdam.MARIN is also co-sponsor of the event.
At this edition of the HISWA Symposium the rapidly evolving views on energy consumption and distribution onboard yachts will be revealed by the presentation of international research results.
The HISWA Symposium on Yacht Design and Yacht Construction is an initiative by the HISWA Association, the Delft University of Technology and Amsterdam RAI. Further information and the programme are available at www.hiswasymposium.com.
At this edition of the HISWA Symposium the rapidly evolving views on energy consumption and distribution onboard yachts will be revealed by the presentation of international research results.
The HISWA Symposium on Yacht Design and Yacht Construction is an initiative by the HISWA Association, the Delft University of Technology and Amsterdam RAI. Further information and the programme are available at www.hiswasymposium.com.
Abstract
"Decreasing frictional resistance by air lubrication"
Evert-Jan Foeth
The decrease of ship resistance is one of the most effective way to reduce operating costs and CO2 production. The wave making resistance and form drag can be reduced by optimizing the hull form, but the frictional drag remains proportional to the wetted surface. The use of air as a lubricant in order to reduce that frictional drag is an active research topic and three techniques are identified: injecting air bubbles in the boundary layer, the use of air films along the bottom plating, and using air cavities in the ship's bottom. These approaches are the research topic for the Dutch joint-research project PELS and the EU project SMOOTH, both of which have the goal of not only predicting energy savings using numerical models and model tests, but proving it using full-scale demonstrator ships adapted for air lubrication. Although decreases in frictional resistance of nearly 20% have been obtained on model-scale ships, experience shows that the implementation of air lubrication can also easily increase the resistance of a ship.
"Decreasing frictional resistance by air lubrication"
Evert-Jan Foeth
The decrease of ship resistance is one of the most effective way to reduce operating costs and CO2 production. The wave making resistance and form drag can be reduced by optimizing the hull form, but the frictional drag remains proportional to the wetted surface. The use of air as a lubricant in order to reduce that frictional drag is an active research topic and three techniques are identified: injecting air bubbles in the boundary layer, the use of air films along the bottom plating, and using air cavities in the ship's bottom. These approaches are the research topic for the Dutch joint-research project PELS and the EU project SMOOTH, both of which have the goal of not only predicting energy savings using numerical models and model tests, but proving it using full-scale demonstrator ships adapted for air lubrication. Although decreases in frictional resistance of nearly 20% have been obtained on model-scale ships, experience shows that the implementation of air lubrication can also easily increase the resistance of a ship.
November 10, 2008