Underwater Drag-Reducing Effect of Superhydrophobic Submarine Model

TLDR

The study demonstrates that superhydrophobic coatings reduce underwater drag on large submarine models, as shown by sailing experiments comparing coated and uncoated models under identical conditions. Superhydrophobic coatings were fabricated by immobilizing hydrophobic copper particles onto a pre‑cross‑linked PDMS surface, with the cross‑linking time optimized to 20 min to achieve optimal wettability and water‑adhesion properties. The coated models achieved up to a 15 % drag reduction, indicating that superhydrophobic coatings hold promise for reducing vehicle drag in water.

Abstract

To address the debates on whether superhydrophobic coatings can reduce fluid drag for underwater motions, we have achieved an underwater drag-reducing effect of large superhydrophobic submarine models with a feature size of 3.5 cm × 3.7 cm × 33.0 cm through sailing experiments of submarine models, modified with and without superhydrophobic surface under similar power supply and experimental conditions. The drag reduction rate reached as high as 15%. The fabrication of superhydrophobic coatings on a large area of submarine model surfaces was realized by immobilizing hydrophobic copper particles onto a precross-linked polydimethylsiloxane (PDMS) surface. The pre-cross-linking time was optimized at 20 min to obtain good superhydrophobicity for the underwater drag reduction effect by investigating the effect of pre-cross-linking on surface wettability and water adhesive property. We do believe that superhydrophobic coatings may provide a promising application in the field of drag-reducing of vehicle motions on or under the water surface.