Page 18: of Maritime Reporter Magazine (February 2026)

The Path to Zero

The simulations show: air bubbles are not stable as they are not attached to the surface. • consistent jet attachment, Future CFD work will also examine the use of pulsating • robust, continuous air entrainment, Coanda jets as an alternative to continuous jet operation. Prior • stable vacuum pressure within the air sheet, studies indicate that pulsed liquid jets can form stable Coanda- • and formation of a stable air sheet that adheres to the hull. attached ? ows while propagating further underwater due to

Initially, the vacuum air sheet was observed at high-pressure vortex structures that reduce jet-core friction. For the same cases, including cases where the nozzles were speci? ed as ca- nominal power, pulsed jets may generate higher instantaneous pable of 8000 psi and 10mm nozzle ori? ce diameter. Initially, pressures and lower average energy consumption because no 3 nozzles were used to develop an air sheet (Figure 3). More power is used during the off-cycle. This behavior entails po- recent cases have focused on using single underwater jet and tential for improved air sheet generation ef? ciency, which will pressures as low as 300 psi and nozzle ori? ce as low as 0.5mm be investigated through further CFD studies.

(Figure 4). Figure 4 (right) also shows the differences between excess air bubbles emanating from the habitat (in red) and the System Con? gurations vacuum air sheet (in blue) attached to the hull. The vacuum air Nozzles may be placed along the bow, midship, bottom, and sheet is stable and unique to this system, while the pressurized stern sections, depending on hull form. Pump con? gurations

Figure 4: Single jet ? xed below waterline – contours of volume fraction (left) and isosurface of 0.5 volume fraction (right).

Figure 5: Pressure distribution across the air sheet (perpendicular to the hull) showing the negative pressure region.

18 Maritime Reporter & Engineering News • February 2026

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