search.noResults

search.searching

dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
ventilation in waves History was made on May 22 when the first-ever


cavitating and ventilating images appeared on the monitors at MARIN’s new Depressurised Wave Basin.


A


Tip vortex and leading edge cavitation during a wave trough, with ventilation vortex crossing the tip vortex cavitation downstream.


t that moment, a 10 m cruise vessel model was sailing in waves under a very low atmos-


pheric pressure. Meanwhile, in the control room of the basin, five MARIN employees were staring at the monitors and then there was much excitement as the first images of slowly arising and dissipating cavitating and ventilating vortices appeared.


This was the first time the new DWB, which was inaugurated in March (see Report Nr. 105), was given the chance to prove its capabilities and highlight its capacity to provide breakthrough research. The DWB is a unique facility worldwide, representing a combination of a depressurised towing tank with a wave maker.


Ventilation and cavitation during a wave trough. A double vortex system is originating from blade 3. Ventilation around the tip com bined with cavitation on blade 4. Cavitation inception on blade 1.


The air pressure in the entire basin was lowered to 50 mbar to give the correct conditions for propeller cavitation, while at the same time the wave makers were operated to simulate a 5 m wave height for the ship model. With this combination, cavitation and the ventilation of propellers in operational conditions can be investi- gated, a capability that is not present anywhere else in the world.


Gerco Hagesteijn & Joris Brouwer


g.hagesteijn@marin.nl 10 report


These innovative tests were carried out for the EU-funded STREAMLINE research pro- gramme, which focuses on fuel efficiency and is driven by increasing environmental concerns and soaring oil prices.


First images of cavitation and


New propulsion concepts STREAMLINE is a response to the demand for more advanced vessels and for radically new propulsion concepts, which deliver a step-change in efficiency. The STREAMLINE consortium, led by Rolls-Royce, comprises 22 partners from eight countries, providing world leading expertise from the European Union’s marine Industry.


Over a four-year time period, the research programme will address several issues. One key objective is to demonstrate that radically new propulsion concepts can deliver an increase in efficiency of at least 15% over current state-of-the-art systems. STREAMLINE will also investigate methods to fully optimise current systems such as conventional screw propeller systems, pods and water-jets. MARIN is involved in various ways, from


136832


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24