Journal
NATURE COMMUNICATIONS
Volume 12, Issue 1, Pages -Publisher
NATURE PORTFOLIO
DOI: 10.1038/s41467-021-26128-8
Keywords
-
Categories
Funding
- Deep Science Fund of Intellectual Ventures
- Australian Government
- Government of Western Australia
Ask authors/readers for more resources
Skin-friction drag can be decreased by oscillatory motion in the surface at high Reynolds numbers, with two distinct pathways for drag reduction identified: one involving frequencies comparable to small-scale eddies and the other involving frequencies comparable to large-scale eddies. The second pathway offers more efficient drag reduction at higher Reynolds numbers, presenting new opportunities for reducing fuel consumption and increasing power generation.
Simulations and experiments at low Reynolds numbers have suggested that skin-friction drag generated by turbulent fluid flow over a surface can be decreased by oscillatory motion in the surface, with the amount of drag reduction predicted to decline with increasing Reynolds number. Here, we report direct measurements of substantial drag reduction achieved by using spanwise surface oscillations at high friction Reynolds numbers (Re-t) up to 12,800. The drag reduction occurs via two distinct physical pathways. The first pathway, as studied previously, involves actuating the surface at frequencies comparable to those of the smallscale eddies that dominate turbulence near the surface. We show that this strategy leads to drag reduction levels up to 25% at Re-t = 6,000, but with a power cost that exceeds any drag-reduction savings. The second pathway is new, and it involves actuation at frequencies comparable to those of the large-scale eddies farther from the surface. This alternate pathway produces drag reduction of 13% at Re-t = 12,800. It requires significantly less power and the drag reduction grows with Reynolds number, thereby opening up potential new avenues for reducing fuel consumption by transport vehicles and increasing power generation by wind turbines.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available