DNV GL Adds Bunker-Saving Asymmetric Stern Design to Hull Optimisation Service

DNV GL can offer optimised asymmetric sterns using CFD and parametric formal optimisation. Image: DNV GL

DNV GL today announced that, using high-fidelity computer fluid dynamics (CFD) and parametric formal optimisation, the classification society now offers ship owners the option of incorporating a bunker-saving asymmetric stern into their new vessels through its ECO Lines hull optimisation service.

"Basically, what we are now able to do is model an aft shape that acts as a propulsion improving device, without the vibration and fatigue strength concerns that come with fins and nozzles," said Karsten Hochkirch, Head of Department, Fluid Engineering at DNV GL – Maritime.

"Using our in-house formal parametric optimisation procedure, we can assess hundreds of options until we find a design that strikes an optimal balance between pre-swirl and resistance, while meeting the design requirements of the customer."

Hochkirch notes that, in a recent project, a 3,000 TEU container ship was optimised with a asymmetric design that achieved a propulsion power reduction of more than 3 percent - a result confirmed during tank testing.

In another project, CFD optimisation generate a design for a 38,000 DWT tanker that promised a 3.5 percent decrease in propulsion power compared to the symmetrical design.

"This is another instance where advances in computing power and software sophistication are enabling us to unlock efficiencies in ship design. By accurately simulating the performance of these complex hull forms, we are achieving propulsion power improvements of up to 5 percent, with greater structural robustness," said Hochkirch.

"Because yards are now able to utilise advanced CAD/CAM techniques and modern, CNC-controlled fabrication methods, they can bring these designs into production much more easily and economically."

As Ship & Bunker previously reported, DNV GL and Jotun Group (Jotun) hosted the second Hull Performance & Insight Conference (HullPIC) at Germany's Castle Ulrichshusen, from March 27 to 29, 2017 - an event that focused on the new ISO 19030 standard, as well as advances in measurements of hull and propeller performance.