On the influence of biomimetic shark skin in dynamic flow separation. (11th March 2021)

• Record Type: Journal Article
• Authors: Guo, Pengming; Zhang, Kai; Yasuda, Yuji; Yang, Wenchao; Galipon, Josephine; Rival, David E
• Is Part Of: Bioinspiration & biomimetics. Volume 16:Number 3(2021)
• Publication Date: 2021-03-11
• Subjects: shark skin -- maneuverability -- flow separation; Biomimetics -- Periodicals; Biomedical materials -- Periodicals; Medical innovations -- Periodicals; Biomedical engineering -- Periodicals; 600
• DOI: 10.1088/1748-3190/abdf31
• Languages: English
• ISSNs: 1748-3182

Abstract

Abstract: The effect of shark skin on the boundary-layer separation process under dynamic conditions (maneuvers) has been studied experimentally. We use a foil covered with biomimetic shark skin to explore how this type of surface impacts boundary-layer dynamics in both steady and accelerating conditions. The effect of denticles is assessed via particle image velocimetry in the wake. It is shown that dynamic conditions and small-scale disturbances can mitigate boundary-layer separation through instantaneous modification of the local pressure-gradient distribution. For instance, the region of favourable pressure gradient can be extended by accelerating the foil. The acceleration results in a thinner separated shear layer on the foil surface when compared to the steady reference case. This remarkable difference indicates that local roughness (introduced through for instance biomimetic shark skin) may trigger an interaction with relatively large-scale structures in the boundary layer for effective boundary-layer control during unsteady propulsion and maneuvering.