Study on the design, fabrication and drag reduction of ridge-type riblet surfaces based on the thin film buckling method

Micro-riblet drag-reduction technology has been developed and applied in aerospace and marine industries to save fuel and cut costs. However, the cost-effective, straightforward and rapid fabrication of riblet surfaces remains a significant challenge. In this paper, drag-reduction surfaces are fabricated using ultraviolet (UV)-induced bending of pre-stretched polydimethylsiloxane. This study examines how substrate pre-stretching ( γ ) and UV exposure duration affect the ridge-riblet geometry and formation mechanisms. Furthermore, regular ridge-type riblets were fabricated, and both experimental and numerical investigations of drag reduction were conducted. The experimental data show that the ridge riblets achieve a drag-reduction rate of 6.10 % at a flow velocity of 2.5 m s −1 ( s Superscript plus Baseline almost equals 16 s + ≈ 16 $s^{+}\\approx 16$ ). Our fabrication process demonstrates distinct advantages over existing drag-reduction structures while achieving comparable levels of drag reduction. We simulate the evolution of velocity, shear stress and vorticity distributions across both smooth and riblet surfaces, thereby elucidating the fundamental mechanisms underlying drag reduction. This research provides an effective method for riblet drag-reduction structure.