Skin friction typically accounts for 70-90 % of total drag on freight ships, and more than 90 % in pipelines. Surface technologies to reduce the skin friction can reduce the energy consumption significantly and enable higher speeds, both through pipelines and for ships.
INSVIVIA has researched various surface technology applications, i.a. for reducing surface tension and to change velocity profiles. CFD-analyses show potentials to reduce the skin friction by up to 95 % with a so-called full slip-length. Thermal and electrical-induced effects can change the property of the surface membrane of various liquids to stabilize cavity films and make them propagate.
Future ship design
SWATH (small waterplane area twin hull) works like a platform carried by two submarines (submerged hulls). This allows the hull to move completely horizontally through waves, and with low wave-making resistance.
The side effect of SWATH is large wet surface area which increase the skin friction. Supercavitation cancels this friction by separating the hull from the water. Thereby, the ships can move at high speed levels within a cavity, like supercavitating missiles.
Although supercavitating SWATHs potentially can move at high speeds with low energy consumption, they have big stability challenges, both in order to stabilize the cavity and the ship as a whole. The counter-rotating hulls solve this by changing the pressure profile of the hull with radial steering, beside the gyroscopic effect of the rotation.
Faster and fewer ships
Travelling at high speeds, one ship can transport the same tonnage per unit time as 4-6 ships today; an oversea travel is made within 2 days instead of 2 weeks. Combined with future nuclear fusion reactors, the technology have potential to upscale the speed level even further due to the small waterplane area, stability and supercavitation.