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Asymptotic turbulent friction in 2D rough-walled flows
Alexandre Vilquin1, Julie Jagielka1, Simeon Djambov1
1Laboratoire Ondes et Matière d'Aquitaine, UMR 5798 Université Bordeaux et CNRS, 351 cours de la Libération, 33405 Talence, France.
Science Advances
|January 30, 2021
Summary
Friction in two-dimensional soap film flows scales linearly with roughness, unlike three-dimensional pipe flows where it scales with roughness to the power of one-third. This discovery challenges standard friction theories.
Area of Science:
- Fluid dynamics
- Turbulence research
- Surface science
Background:
- Friction (f) in wall-bounded flows impacts practical applications like pipeline pumping costs and river draining.
- In 3D turbulent pipe flows, friction depends on roughness (r) following Strickler's scaling: f ∝ r^(1/3).
Purpose of the Study:
- To experimentally investigate the friction-roughness relationship in two-dimensional (2D) soap film flows.
- To compare the 2D friction behavior with established 3D turbulent pipe flow dynamics.
Main Methods:
- Experimental analysis of soap film flows.
- Measurement of friction (f) and roughness length scale (r).
Main Results:
- In 2D soap film flows, friction (f) exhibits a linear relationship with roughness (r): f ∝ r.
- The observed f-r relation in 2D differs significantly from the 3D pipe flow scaling.
Conclusions:
- The findings deviate from standard friction theories but align with alternative models linking friction to turbulent spectra.
- The spectral exponent (α) differs between 2D (α=3) and 3D (α=5/3) flows, explaining the distinct friction scaling.
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