| Rainbow trout (Oncorhynchus mykiss)1,12,13,18,19
|
Swimming fish surface |
The particle image velocimetry (PIV) technique |
Flow separation control20–29
|
—19
|
| The sailfish (Istiophorus platypterus)30
|
V-shaped protrusions pointing downstream |
An open-circuit suction-type wind tunnel and floating element apparatus |
Without obvious drag reduction effect |
—30
|
| Boxfish |
The shape of the carapace in boxfishes |
Computational fluid dynamics simulations |
Destabilizing flow over the boxfish's body promotes manoeuvrability |
The drag coefficient of about 0.1531
|
| Fossil of sharks11,32,33
|
Riblets |
Examine the diverse adaptions and review the few attempts |
Streamlined and separated control34
|
—11
|
| Fossil of sharks |
Shark scales |
Analyzed the fossil record of shark scales |
62% as drag reduction scales |
—32
|
| Hawaiian stream fish (Sicyopterus stimpsoni) |
Adsorption climbing |
Climbing trials up artificial waterfalls |
Low head height exposed to high fluidity |
—35
|
| European sea bass (Dicentrarchus labrax) |
Fish scale pattern |
A flow channel mimic and computational fluid dynamics simulations |
Low-speed and high-speed streaks inside the boundary layer and delay transition36–38
|
9% (20 cm s−1)39
|
| The fish (Ctenopharyngodon idellus)40,41
|
Geometric structure of crescent-like ridge |
Numerical simulations and theoretical calculations |
The “water-trapping” effect40–42
|
3.014% (0.66 m s−1)41
|
| The bonnethead shark (Sphyrna tiburo) |
The flexible 3D printed shark skin |
3D printed shark skin under dynamic conditions |
A leading-edge vortex with greater vorticity than the smooth control |
6.6%43
|
| Shark |
Simulated shark denticle |
Numerical simulations and optimization |
Wake vortex suppressed1,12,44–48
|
—49
|
| The shortfin mako (Isurus oxyrinchus)5,20,27,43,50–53
|
Shark skin |
Time-resolved digital particle image velocimetry (TR-DPIV) |
Scale bristling controls flow separation5,27,50,52
|
—36
|
| A male shortfin mako shark |
Flexible shark skin foil |
Digital particle image velocimetry (DPIV) and control shark skin movement |
Denticles promote enhanced leading-edge suction |
12.3%53
|
| Swimming bottlenose dolphins (Tursiops truncatus)54,55
|
Dolphin skin |
Digital particle image velocimetry (DPIV) |
Anisotropic compliant wall and intermittent wave motion56–60
|
—54
|
| Odontocetes |
The ridged skin |
Silicone moulding compound to make moulds |
Smooth skin and flexibility61
|
—62
|
